If you have a developer account that you are willing to sacrifice and don't mind the possibility of legal action, you can try that. I've managed to upload the binary built from the source code from gamed exploit repository on GitHub to App Store Connect and installed it onto my own device via TestFlight. I didn't submit it for review, but if the functionality would have been concealed, it would easily pass.

As far as I know, how the review happens is that reviewers just install apps onto their iPads, tap through all the screens they can find and make their decisions based purely on that. So if an app connects to server and asks what it should do, it's possible to make an app behave differently for reviewers and all other users.