I'm trying to disable radios for things like WiFi, BT, GPS, and any other telemetry from the system level on AOSP. Specifically, I'm trying to do it in a quick-settings tile or an item on the shutdown menu, but I'm not quite sure how to embark on this task. I can make APKs and quick-settings tiles, but I don't know how to access radios on a low level, setting them to off, not dormant.
Airplane mode does the same. You can look into Airplane mode implementation and can do similar implementation for your requirement.
Once Airplane mode is changed, ConnectivityService broadcasts ACTION_AIRPLANE_MODE_CHANGED action to all the radio classes (WiFi, Bluetooth, Network, etc.). Based on this action device's radio is turned off.