We actually used to have MFI controller support with the joystick controlled and ... But it was never used. Checking our analytics literally no one ever used the functionality. So we never kept up with it. Even apple never really advertised it after their original launch of the functionality.... At least until they announced iOS13. With iOS13 it looks like they are breathing some new life into it now that it can support Xbox and PS4 controllers.
Maaaaybe if Apple doesn't drop the ball on the launch and controller support becomes more popular we'll look at supporting it again.