Add the following code to your theme’s functions.php file.
// Hide the google site kit menu
function hide_plugin() {
remove_menu_page('googlesitekit-dashboard');
remove_submenu_page('googlesitekit-dashboard', 'googlesitekit-splash');
}
add_action('admin_menu', 'hide_plugin', 100);
// remove tool bar item
function remove_toolbar_node($wp_admin_bar) {$wp_admin_bar->remove_menu("google-site-kit");
}
add_action("admin_bar_menu", "remove_toolbar_node", 100);