Update Jpa Entity with Relationship using DTO

Question

I have a entity that contains other entities. I'm getting data from ProductDTO, and i need get ids (each id can change or don't) and set it to entity.

In my Service i get the actual product, get each entity by id and set in product entity. But don't seems be the best approach fetch each entity on respective repository.

My entity:

@Entity
public class Product implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;
  private Status status;
  private Location location;
  private Provider provider;
}

My DTO:

public class ProductDTO {
  private Long statusId;
  private Long locationId;
  private Long providerId;
}

My service:

     Product p = productRepository.findById(id)
            .orElseThrow(() -> new EntityNotFoundException("Product ID " + id + " not 
     found."));

    var status = userRepo.findById(dto.getStatusId());
    var location = locationRepo.findById(dto.getLocationId());
    var provider = providerRepo.findById(dto.getProviderId());
    p.setStatus(status);
    p.setLocation(location);
    p.setProvider(provider);

There is a best aprroach to update a entity that contains others entities without fetch each one?

Thanks.