How to work with NavigationBar in go_router? | Flutter

Question

I am currently struggling refactoring my routing code with go_router.

I already got some simple routes like /signin & /signup, but the problem comes in when I try to make the routing work with a BottomNavigationBar that has multiple screens. I would like to have a separate route for each of them like /home, /events & /profile.

I figured out that I somehow have to return the same widget with a different parameter to prevent the whole screen to change whenever a BottomNavigationBarItem is pressed and instead only update the part above the BottomNavigationBar which would be the screen itself.

I came up with a pretty tricky solution:

GoRoute(
  path: '/:path',
  builder: (BuildContext context, GoRouterState state) {
    final String path = state.params['path']!;

    if (path == 'signin') {
      return const SignInScreen();
    }

    if (path == 'signup') {
      return const SignUpScreen();
    }

    if (path == 'forgot-password') {
      return const ForgotPasswordScreen();
    }

    // Otherwise it has to be the ScreenWithBottomBar

    final int index = getIndexFromPath(path);

    if (index != -1) {
      return MainScreen(selectedIndex: index);
    }

    return const ErrorScreen();
  }
)

This does not look very good and it makes it impossible to add subroutes like /profile/settings/appearance or /events/:id.

I would like to have something easy understandable like this:

GoRoute(
  path: '/signin',
  builder: (BuildContext context, GoRouterState state) {
    return const SignInScreen();
  }
),
GoRoute(
  path: '/signup',
  builder: (BuildContext context, GoRouterState state) {
    return const SignUpScreen();
  }
),
GoRoute(
  path: '/home',
  builder: (BuildContext context, GoRouterState state) {
    return const ScreenWithNavBar(selectedScreen: 1);
  }
),
GoRoute(
  path: '/events',
  builder: (BuildContext context, GoRouterState state) {
    return const ScreenWithNavBar(selectedScreen: 2);
  },
  routes: <GoRoute>[
    GoRoute(
      path: ':id',
      builder: (BuildContext context, GoRouterState state) {
        return const EventScreen();
      }
    )
  ]
)

Is there any way to achieve the behavior?