Mapping invoice entity to DTO to safeguard our entity

InvoiceContract.php

<?php

namespace App\Contract;

class InvoiceContract
{
    public readonly int $id;
    public readonly string $invoiceNumber;
    public readonly string $amount;
    public readonly \DateTimeInterface $createdAt;
}

InvoiceController.php

<?php
//...
use App\Mapper\EntityMapperInterface;
use Symfony\Component\Serializer\SerializerInterface;

#[Route('/invoice')]
class InvoiceController extends AbstractController
{
    public function __construct(
      private readonly EntityMapperInterface $entityMapper,
      private readonly SerializerInterface $serializer
    ) {
    }

    #[Route('/{id}', name: 'invoice_show', methods: ['GET'])]
    public function show(Invoice $invoice): JsonResponse
    {
        $invoiceContract = $this->entityMapper->map($invoice, InvoiceContract::class);

        $jsonData = $this->serializer->serialize($invoiceContract, 'json');

        return new JsonResponse($jsonData, 200, [], true);
    }
}