Just today the Chuwi returned to usual! After a reboot from Android to W10 … got again 9861 mWh, with 0% battery wear, really. Still, a bit below the 10,000+ I had for a short while some months back.
So it surely is not WYSIWYG. Don’t ever believe the battery is broken when the tablet suggests it is 😉 perhaps after three years of daily use … And don’t use the switch to hop from one OS to the other, always put it off first and then reboot.