MakeCoolStuff.php

<?php

class MakeCoolStuff extends AbstractController
{
    public function __construct(
        EntityManagerInterface $manager,
        YourFunkyService $service
    ) {
        $this->manager = $manager;
        $this->service = $service;
    }

    public function __invoke(SomeEntityFormRequest $request, User $user): JsonResponse
    {
        $vacancy = $this->service->createFromRequest($request, $user);

        $this->manager->persist($vacancy);
        $this->manager->flush();

        return new JsonResponse([
            'message' => 'Что-то там успешно создано!'
        ]);
    }
}