Remove submenu items from navigation flow to get faster to other content when using Tab?

Question

I have a fly-out menu that looks like this:

In HTML, it looks like this:

<div class="c-header__container">
  <ul class="c-header__menu-container" id="menu-container">
    <li class="c-header__menu-item c-header__menu-item--search">
      <div class="c-header__search-container c-header__search-container--mobile" id="mobile-search"></div>
    </li>

    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--arrow" href="/produkty-pro-zeny">Dámské</a>
      <ul class="c-header__sub-menu-container" ref="subMenu">
        <li class="c-header__sub-menu-item">
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vyprodej-pro-zeny">Výprodej</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping">Kemping</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/produkty-pro-zeny">Zobrazit vše pro ženy</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obleceni-pro-zeny">Dámské oblečení</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/trika-pro-zeny">Trika</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/mikiny-pro-zeny">Mikiny</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/svetry-pro-zeny">Svetry</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/bundy-pro-zeny">Bundy</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kabaty-pro-zeny">Kabáty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kalhoty-pro-zeny">Kalhoty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vesty-pro-zeny">Vesty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/funkcni-pradlo-pro-zeny">Funkční prádlo</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kosile-pro-zeny">Košile</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/capri-pro-zeny">Capri</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saty-a-sukne-pro-zeny">Šaty a sukně</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kratasy-pro-zeny">Kraťasy</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-zeny">Dámská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-zeny">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-zimni-pro-zeny">Zimní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-zeny">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-zeny">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-zeny">Letní obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/doplnky-pro-zeny">Dámské doplňky a příslušenství</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/cepice-a-ksiltovky-pro-zeny">Čepice a kšiltovky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saly-celenky-a-satky-pro-zeny">Šály a šátky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/rukavice-pro-zeny">Zimní rukavice</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/ponozky-pro-zeny">Ponožky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/batohy-tasky-penezenky-pro-zeny">Batohy a tašky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/impregnace-a-prostredky-pro-zeny">Impregnace a prostředky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping-pro-zeny">Kemping</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--arrow" href="/produkty-pro-muze">Pánské</a>
      <ul class="c-header__sub-menu-container" ref="subMenu">
        <li class="c-header__sub-menu-item">
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vyprodej-pro-muze">Výprodej</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping">Kemping</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/produkty-pro-muze">Zobrazit vše pro muže</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obleceni-pro-muze">Pánské oblečení</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/trika-pro-muze">Trika</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/mikiny-pro-muze">Mikiny</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/svetry-pro-muze">Svetry</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/bundy-pro-muze">Bundy</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kalhoty-pro-muze">Kalhoty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vesty-pro-muze">Vesty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/funkcni-pradlo-pro-muze">Funkční prádlo</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kosile-pro-muze">Košile</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/capri-pro-muze">Capri</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kratasy-pro-muze">Kraťasy</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-muze">Pánská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-muze">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-muze">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-muze">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-muze">Letní obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/doplnky-pro-muze">Pánské doplňky a příslušenství</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/cepice-a-ksiltovky-pro-muze">Čepice a kšiltovky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saly-celenky-a-satky-pro-muze">Šály a šátky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/ponozky-pro-muze">Ponožky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/batohy-tasky-penezenky-pro-muze">Batohy a tašky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/impregnace-a-prostredky-pro-muze">Impregnace a prostředky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping-pro-muze">Kemping</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--arrow" href="/produkty-pro-deti">Dětské</a>
      <ul class="c-header__sub-menu-container" ref="subMenu">
        <li class="c-header__sub-menu-item">
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vyprodej-pro-deti">Výprodej</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping">Kemping</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/produkty-pro-deti">Zobrazit vše pro děti</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obleceni-pro-deti">Dětské oblečení</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/trika-pro-deti">Trika</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/mikiny-pro-deti">Mikiny</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/bundy-pro-deti">Bundy</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kabaty-pro-deti">Kabáty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kalhoty-pro-deti">Kalhoty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vesty-pro-deti">Vesty</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/funkcni-pradlo-pro-deti">Funkční prádlo</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sety-a-jine-pro-deti">Sety</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/capri-pro-deti">Capri</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saty-a-sukne-pro-deti">Šaty a sukně</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kratasy-pro-deti">Kraťasy</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-deti">Dětská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-deti">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-zimni-pro-deti">Zimní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-deti">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-deti">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-deti">Letní obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/doplnky-pro-deti">Dětské doplňky a příslušenství</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/cepice-a-ksiltovky-pro-deti">Čepice a kšiltovky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saly-celenky-a-satky-pro-deti">Šály a šátky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/rukavice-pro-deti">Zimní rukavice</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/ponozky-pro-deti">Ponožky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/batohy-tasky-penezenky-pro-deti">Batohy a tašky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/impregnace-a-prostredky-pro-deti">Impregnace a prostředky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping-pro-deti">Kemping</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--arrow" href="/obuv">Obuv</a>
      <ul class="c-header__sub-menu-container" ref="subMenu">
        <li class="c-header__sub-menu-item">
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vyprodej-obuv">Výprodej</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link c-header__sub-menu-category-item--all" href="/obuv">Zobrazit všechnu obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-zeny">Dámská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-zeny">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-zimni-pro-zeny">Zimní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-zeny">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-zeny">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-zeny">Letní obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-muze">Pánská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-muze">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-muze">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-muze">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-muze">Letní obuv</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/obuv-pro-deti">Dětská obuv</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-outdoor-pro-deti">Outdoorová obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-zimni-pro-deti">Zimní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-do-mesta-pro-deti">Městská obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/boty-sportovni-pro-deti">Sportovní obuv</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/sandale-a-zabky-pro-deti">Letní obuv</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--arrow" href="/doplnky">Doplňky</a>
      <ul class="c-header__sub-menu-container" ref="subMenu">
        <li class="c-header__sub-menu-item">
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/vyprodej-doplnky-a-prislusenstvi">Výprodej</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link c-header__sub-menu-category-item--all" href="/doplnky">Zobrazit všechny doplňky</a>
            </li>
          </ul>
        </li>
        <li class="c-header__sub-menu-item">
          <a class="c-header__sub-menu-link" href="/doplnky-pro-zeny">Dámské doplňky a příslušenství</a>
          <ul class="c-header__sub-menu-category-container">
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/cepice-a-ksiltovky-pro-deti">Čepice a kšiltovky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/saly-celenky-a-satky-pro-zeny">Šály a šátky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/rukavice-pro-zeny">Zimní rukavice</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/ponozky-pro-zeny">Ponožky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/batohy-tasky-penezenky-pro-zeny">Batohy a tašky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/impregnace-a-prostredky-pro-zeny">Impregnace a prostředky</a>
            </li>
            <li class="c-header__sub-menu-category-item">
              <a class="c-header__sub-menu-category-link" href="/kemping-pro-zeny">Kemping</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li class="c-header__menu-item">
      <a class="c-header__menu-close" href="#">
        <i class="far fa-times-circle"></i>
      </a>
      <a class="c-header__menu-link c-header__menu-link--discount" href="/vyprodej">Výprodej</a>
    </li>

    <li class="c-header__menu-item c-header__menu-item--profile c-header__menu-item--border">
      <a class="c-header__menu-link c-header__menu-link--my-account js-user-popup-open" href="/muj-profil">
        <i class="far fa-user-circle"></i>
        <span>Můj profil</span>
      </a>
      <div class="c-header__menu-language">
        <a class="c-header__menu-link c-header__menu-link--language c-header__menu-link--active" href="#">CZ</a>
        <a class="c-header__menu-link c-header__menu-link--language" href="#">SK</a>
      </div>
    </li>

    <li class="c-header__menu-item c-header__menu-item--last" id="desktop-search">
      <div class="c-header__search-container" id="search-container">
        <input class="c-header__search-input" id="fulltext-search-input" type="text" placeholder="Vyhledat..." maxlength="50" />
        <a class="c-header__search-close" id="fulltext-search-close" href="#">
          <i class="fas fa-times"></i>
        </a>
        <button class="c-header__search-button" id="fulltext-search-button" title="Vyhledat">
          <i class="fas fa-search"></i>
        </button>
        <div class="c-search-results" id="search-result-container"></div>
      </div>
    </li>
  </ul>
</div>

When I tab over it, the tabbing order looks like this:

It means that every submenu item receives focus. There are a lot of these submenu items, about 120, so it takes some time to tab over them and get to other content, for example to the search box on the right side:

would it make sense to skip all the submenu items? For example setting tabindex="-1" to all of them, so the final tab order would look like this:

It feels like this might improve accessibility because other content is accessible faster when using Tab, especially the search box. All the content accessible via the submenu items could be later accessed from the main categories, so no one would miss any content on the website.

On the other hand, using tabindex="-1" is discouraged on some sites, for example on WebAim.org:

A tabindex="-1" value removes interactive elements from the default navigation flow. In most cases, this would not be desirable.

Remember that tabindex="-1" removes the element from the default navigation flow. Do not assign tabindex="-1" to any element that must be keyboard navigable, such as a link or button that sighted users can click on with the mouse.

I might be missing some reason why this proposed solution of mine is not a good idea. That's what I hope to get some insights on.