This is true. Apple’s excuse for it is that it’s used for FindMy and locking down a stolen device. So the Bluetooth and GPS and/or cellular radio still function with the device “off”.

https://www.macrumors.com/guide/ios-15-find-my/

This is honestly exactly what programming is: breaking down big problems into step by step simple problems. If you’ve never considered taking up programming before, I’d suggest you try it sometime and see where it takes you. It’s not hard to learn, it just takes time.

Gentoo with OpenRC is a good option imo