What is the best practice to fill a DTO class that has only Object Lists [closed]

I have a DTO class with Object lists. Im running simple CRUD operations with my project. Since i need to fill bunch of comboboxes with one service, i just created a comboboxFillerDTO. Basically, what i can do is to call findAll() method for all object lists from their own repositories but i'm wondering if there is a better way to do it?

This my DTO;

@Data
public class ComboboxDTO {

    private List<ContactType> contactTypes;
    private List<DocumentType> documentTypes;
    private List<EnvironmentType> environmentTypes;
    private List<RelationType> relationTypes;
    private List<SpecificationType> specificationTypes;
    private List<ProjectStatus> projectStatuses;
}

Every object from the DTO is an Entity and my repository interfaces uses JpaRepository for basic operations.

Is there a better way other than calling findAll() for every Entity repository in my Service layer?

This is the only way i think is to call repository.findAll() for every object list in DTO;

@Service
@Qualifier("ComboboxFillerService")
public class ComboboxFillerService implements IComboboxFillerService {


    private final ContactTypeRepository contactTypeRepository;
    private final DocumentTypeRepository documentTypeRepository;
        .
        .
        .

    @Autowired
    public ComboboxFillerService(ContactTypeRepository contactTypeRepository, DocumentTypeRepository documentTypeRepository...) {
        this.contactTypeRepository = contactTypeRepository;
        this.documentTypeRepository = documentTypeRepository;
    .
    .
    .
    }


    @Override
    public ComboboxDTO fillComboBox() {


        ComboboxDTO dto = new ComboboxDTO();
        dto.setContactTypes(contactTypeRepository.findAll());
        dto.setDocumentTypes(documentTypeRepository.findAll());
        .
        .
        .

        return dto;


    }
}