code: public function kernelRequest(GetResponseEvent $event)
      {
          $request = $event->getRequest();
          $entity = $request->attributes->get('_api_resource_class');
  
          if (null === $entity) {
              return;
          }
  
          if (!in_array(Translatable::class, class_implements($entity), true)) {
              return;
          }
  
          $model = $request->attributes->get('data');
  
          if ('post' === $request->attributes->get('_api_collection_operation_name')) {
              $this->translationService->transfer($model);
          } else if ('put' === $request->attributes->get('_api_item_operation_name')) {
              $this->translationService->transfer($model);
              $this->translationService->translate($model);
          }
      }
docs: Transfer translations from properties to source before saving them to storage
  
  @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event