How to properly handle my exception not found symfony 4?

Question

symfony

How to properly handle your exception? If I do something like this

public function onKernelException(GetResponseForExceptionEvent $event): void
    {
        $exception = $event->getException();
        $response = $event->getResponse();
        //dd($exception, $response);
        if ($exception instanceof NotFoundException) {
            $event->setResponse(new Response($exception->getUserMessage(), $exception->getCode()));
        }
    }

then I just get a 404 in response and display my text, but it does not look like a 404 error and symphony and I suspect the 404 error template will not connect in this case either.
Can you do it like this

public function onKernelException(GetResponseForExceptionEvent $event): void
    {
        $exception = $event->getException();
        $response = $event->getResponse();
        //dd($exception, $response);
        if ($exception instanceof NotFoundException) {
            $event->setException(new NotFoundHttpException($exception->getUserMessage()));
        }
    }

but it seems to me that this is not true.