MonkeyLock blocks the apps you choose using Apple's Screen Time. When your minutes run out they lock, and you get them back by doing push-ups — the front camera counts the reps on device. Nothing is recorded or uploaded.
The part I think is actually new: adding an app to the wall is instant, but taking one off waits until the next morning. Every blocker I tried could be undone in ten seconds, which is exactly when it was working.
Free. No subscription, no ads, no account.