Here is the discharge rate of my @droidian phone last night (Redmi Note 9 Pro).
I've been working on a kernel module heavily inspired by Batman, and the results exceed my expectations.
This is with my Signal client (Flare) running and my PineTime connected via Bluetooth (Watchmate).
https://github.com/bellegarde-c/linux-android-xiaomi-miatoll/commits/powersaver/
Remember that on Linux, applications are not freezed... Will do more tests with more apps running.