Allowing a custom user role to add a category on a custom post type in Wordpress

Question

I am attempting to create a custom user role named "Debater" that can create/edit/manage a custom posted type of "debates" as well as a custom taxonomy for these debate posts.

I have managed to get this working except for the ability to allow the custom user to apply categories to the debate posts they author. The site administrator can apply categories as need.

Not sure what I am missing, but it is probably a blinding flash of obvious.

<?php
defined("ABSPATH") or die();

//Register user role when activating plugin

register_activation_hook(__FILE__, "deb_activation");

//Remove  user role on deactivation

register_deactivation_hook(__FILE__, "deb_deactiviation");

function deb_activation(){
    $caps = array( 
        'read'          => true,  
        'create_post'    => true, // Allows user to create new posts
        'edit_post'      => true 
    );
    add_role( 'Debater', 'Debater', $caps );
}

function deb_deactiviation(){
    remove_role("Debater");

}
// 


add_action("init","debate_post_types");
function debate_post_types(){
    //Set up the debate post type
            register_post_type("debates", array(
                //for the archive, it uses the register post type name parameter, not the label
                //or url rewrite
                "has_archive" => true,
                'menu_position' => 30,
                'label'  => 'Debates',
                "public" => true,
                "show_in_rest" => true,
                "menu_icon" => "dashicons-format-chat",
                "description" => "A list of debates",
               
                "labels" => array(
                    "name" => esc_html("Debates","debate-plug"),
                    "add_new_item" => esc_html("Add New Debate","debate-plug"),
                    "add_new" => esc_html("Add New","debate-plug"),
                    "edit" => esc_html("Edit", "debate-plug"),
                    "edit_posts" => esc_html("Edit Posts", "debate-plug"),
                    "edit_item" => esc_html("Edit Your Debate", "debate-plug"),
                    "new_item" => esc_html("New Debate", "debate-plug"),
                    "view" => esc_html("View Debates", "debate-plug"),
                    "view_item" => esc_html("View Debate", "debate-plug"),
                    "all_items" => esc_html("All Debates", "debate-plug"),
                    "search_items" => esc_html("Search Debates", "debate-plug"),
                    "not_found" => esc_html("No Debates Found", "debate-plug"),
                    "not_found_in_trash" => esc_html("No Debates Found in Trash", "debate-plug"),
                    "singular_name" => esc_html("Debate","debate-plug")
                ),
                //'rewrite' => array( 'slug' => 'intense-debates' ),
                "supports" => array(
                    "title",
                    "editor",
                    "excerpt"
                ),
                
                "capability_type" => array("debate","debates"),
                "map_meta_cap" => true,
                "hierarchical" => true
                )
            );
    }
    
//add role capabilities

add_action("admin_init", "deb_role_caps", 999);

function deb_role_caps(){
    //add the roles that can administer the debate posts
    $roles = array("Debater");

    foreach($roles as $the_role){
        $role = get_role($the_role);
        $role->add_cap("read");
        $role->add_cap("read_debates"); //must match post type
        $role->add_cap("read_private_debates");
        $role->add_cap("edit_debates");
        $role->add_cap("edit_other_debates");
        $role->add_cap("edit_published_debates");
        $role->add_cap("publish_debates");
        $role->add_cap("delete_others_debates");
        $role->add_cap("delete_private_debates");
        $role->add_cap("delete_published_debates");
    }



}

//Set up debate Topic Hierarchy 

function register_debate_taxonomy() {
    $args = array( 
        'hierarchical' => true,
        'label' => 'Debate Topics',
        'show_ui'               => true,
        'show_admin_column'     => true,
        'query_var'             => true,
        'show_in_rest'          => true,
    );
    register_taxonomy( 'debate-topics', 'debates', $args );
}
add_action( 'init', 'register_debate_taxonomy' );