How to avoid services in DtoMappers layer

Good day, I have a Spring Boot based backend , we are using own library to convert JPA entities to Dto's (library works based on reflection). The problem is , we inject service layer directly to some mappers. Let's say I have a UserEntity and UserDto. UserDto has a field called avatar and avatars are stored in S3. So in order to build a UserDto we are using the code like this.

@Component
class UserMapper {

 @Inject
 S3Service s3Service;

 public UserDto toDto(UserEntity entity){
     UserDto dto = new UserDto();
     BeanUtils.copy(entity,dto);
     dto.setAvatar(s3Service.getAvatarByUser(entity));

}

}

I don't like this approach because Mapper mustn't know anything about Service layer . However this mapper is used by other mappers as well. In case I want to return an OrderDto, it has a nested UserDto so OrderDto calls UserMapper internally. Are there any best practices for Mappers to be service free ?

So far I tried the following.

1. Store avatar in ThreadLocal cache. When controller calls a service to get a user, service will store user's avatar in the ThreadLocal, and then Mapper will get it from ThreadLocal cache. Disadvantage - it's hard to test it and requires me to make Mocks
2. Create a separate POJO called UserWithAvatar that stores UserEntity entity;String avatar and create a mapper for UserWithAvatar instead of UserEntity. Disadvantage - as I said this mapper will be used by OrderMapper and order mapper takes OrderEntity with nested UserEntity instead of UserWithAvatar