sort staff and client by first name

ts.php

             'users' => [],
         );
         //search all users that are staff
-        $staffq = new \WP_User_Query(array('role'=>'staff'));
+        $staffq = new \WP_User_Query(array('role'=>'staff','meta_key'=>'first_name', 'orderby'=>'meta_value', order=>'ASC'));
         $staff = $staffq->get_results();
         if (! empty($staff)){
             $response['status'] = 'success';
             'users' => [],
         );
         //search all users that are staff
-        $clientq = new \WP_User_Query(array('role'=>'client'));
+        $clientq = new \WP_User_Query(array('role'=>'client', 'meta_key'=>'first_name', 'orderby'=>'meta_value', order=>'ASC'));
         $client = $clientq->get_results();
         if (! empty($client)){
             $response['status'] = 'success';
     
     private function get_people_by_role($role){
         //search all users that are staff
-        $staffq = new \WP_User_Query(array('role'=>$role));
+        $staffq = new \WP_User_Query(array('role'=>$role, 'meta_key'=>'first_name', 'orderby'=>'meta_value', order=>'ASC'));
         $staff = $staffq->get_results();
         return $staff;
     }