Remove WordPress admin bar from backend

functions.php

<?php

add_filter('ure_role_additional_options', 'add_remove_adminbar_from_backend_admin_option', 10, 1);


function add_remove_adminbar_from_backend_admin_option($items) {
    $item = URE_Role_Additional_Options::create_item('prohibit_admin_access', esc_html__('Remove admin bar from backend', 'user-role-editor'), 'admin_init', 'remove_adminbar_from_backend');
    $items[$item->id] = $item;
    
    return $items;
}

function remove_adminbar_from_backend() {

  wp_deregister_script('admin-bar');
  wp_deregister_style('admin-bar');
  
  remove_action('admin_init', '_wp_admin_bar_init');
  remove_action('in_admin_header', 'wp_admin_bar_render', 0);

  add_action('admin_head', 'fix_adminbar_padding');

}


function fix_adminbar_padding() {
?>
   <style>
      body.admin-bar, body.admin-bar #wpcontent, body.admin-bar #adminmenu {
          padding-top: 0px !important;
      }
      html.wp-toolbar {
          padding-top: 0px !important;
      }
   </style>
<?php                    
}