Manual launch?
So the app does not auto launch. Ok. The app asks you to keep it in the background. Ok. The app asks you to manually set the alarm each time you plug the charger? Really? Please check the battery alarms for android phones to see how those are supposed to work. You give the app permission to auto launch and be ignored by auto kill. That’s it. The app runs every time I plug charger and runs the alarm at the set percentage. I bought one for my android devices, but for my iPad Pro 2021 there’s obviously no alternative.