Best I've found is 'cpu info' on F-Droid, it shows the battery health and other useful hardware stats. I checked on 4 devices (2 year old, 2 year old, 4 year ol

Best I've found is 'cpu info' on F-Droid, it shows the battery health and other useful hardware stats. I checked on 4 devices (2 year old, 2 year old, 4 year old, 8 year old) and all reported battery health as 'Good', so not super detailed.