Redirect from /my/TAIL to /user/{uid}/TAIL

my_redirect.route:
 path: '/my/{tail}'
 defaults:
   _controller: '\Drupal\my_redirect\Controller\MyRedirectController::redirect'
   _title: 'My Redirect'
 requirements:
   _permission: 'access content'

namespace Drupal\my_redirect\Controller;
use Drupal\Core\Controller\ControllerBase;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpFoundation\Request;
class MyRedirectController extends ControllerBase {
 public function redirect($tail, Request $request) {
   $current_user = \Drupal::currentUser();
   if ($current_user->isAuthenticated()) {
     $uid = $current_user->id();
     $destination = "/user/$uid/" . $tail;
     return new RedirectResponse($destination);
   }
   return new RedirectResponse('/user/login');
 }
}