ok, that makes more sense. If the battery is dead then the phone can't track me (or if you had a phone with a removable battery - i have an old one I kept that is like that).
No part of the phone is controlled by me. Can we stop getting spooked by the word "baseband" yet? It means the modem chip. The modem chip isn't controlled by me and can wake up without my knowledge. But neither is the wifi chip. Or the bluetooth chip. Or the RAM chip. Or the main CPU (application processor). Or the screen. Any one of these could hold malware.
It’s less clear what is the “art of the possible” vs. practical for people who aren’t actively under surveillance.