List subsites from mainsite

I would like to hide the admin bar in my subsites and list a subsite for the site admins from the main site, for the main site I created the function:

if ( is_user_logged_in() && is_admin()) {

add_filter('wp_nav_menu_items', 'my_sites', 10, 2);
function my_sites($items, $args) {
$items .= '<li> <a href="/wp-admin/my-sites.php"> My Sites </a></li>';
return $items;

To add a menu item when the user is logged, but I’m having a problem to send the link to a subsite URL

It would depend on the admin ID to create a URL like subsite/wp-admin/my-sites.php

Any Idea?