Focusone

Focusone is a screen time and habit-building app built on Apple’s Family Controls and DeviceActivity frameworks. Because the limits are enforced by iOS itself rather than by a timer inside an app you can close, they hold up on the days you would rather they did not.

You pick the apps to shield, set the windows where they stay shut, and build up the habits you are actually trying to keep. Premium features run on a subscription handled through StoreKit.