• I have a post type called "PRO".
• I have a custom taxonomy for above post type called "Pro Categories".
• Admin will create users in the backend with a custom role called "Pro Access"
• Admin will create custom taxonomy term and while creating he must choose a user with the above role (So only the list of users with the above role must be visible to choose)
• In the front end, when the user logs in, he must see (or have access to) only taxonomies / posts that his profile has access to. There is no backend access to users. Just front end restriction

• Created user role using user role editor
• Using ACF pro, user relation field, i am displaying all the users related to "pro access" in taxonomy section.
• Created Two taxonomies and two users and tagged them to check the results

• I have a post type called "PRO".
• I have a custom taxonomy for above post type called "Pro Categories".
• Admin will create users in the backend with a custom role called "project"
• Admin will create custom taxonomy term and while creating he must choose a user with the above role (So only the list of users with the above role must be visible to choose)
• In the front end, when the user logs in, he must see (or have access to) only taxonomies / posts that his profile has access to. There is no backend access to users. Just front end restriction

• Created user role using user role editor
• Using ACF pro, user relation field, i am displaying all the users related to "project" in taxonomy section.
• Created Two taxonomies and two users and tagged them to check the results

So far what i achieved.

• Created user role using user role editor
• Using ACF pro, user relation field, i am displaying all the users related to "pro access" in taxonomy section.
• Created Two taxonomies and two users and tagged them to check the results

Below is the code which checks wether current user has access to taxonomy tagged or not.

$current_user = wp_get_current_user();   
                if(in_array('project',$current_user->roles)){
                    $pro_cats = get_terms('pro-category','hide_empty=0');
                    //print_r( $pro_cats); 

                    $allowed_cats = array();
                    if(is_array($pro_cats) && count($pro_cats)){
                        foreach($pro_cats as $pro_cat){
                            $auth_users = get_field('authorized_users', 'pro-category_'.$pro_cat->term_id);
                            if(is_array($auth_users) && count($auth_users)){
                                foreach($auth_users as $auth_user){
                                    if($auth_user['ID'] == $current_user->ID){
                                        $allowed_cats[] = $pro_cat;
                                    $link = get_bloginfo( 'url' ) . '/pro-category/' . $pro_cat->slug . '/';
                                    echo 'Name - '.$pro_cat->name.' - link -'.$link.'<br />';
                                        //print_r( $pro_cat->name);
                                        //print_r( $pro_cat->slug);
                                    }
                                }
                            }
                        }
                    }
                }

So from the above, when user logs in, i can see what taxonomy he is tagged in.

Now, I wanted to put restriction on taxonomy archive / single posts. So when a user is logged in, he must access only taxonomies related to his profile.