After I first installed watchOS 10.0 I had incredibly poor battery life. Talking 5-6 hours of usage. After a few reboots and a couple of days things evened out.
With 10.1, I have had the worst update experience I have ever had from an Apple device. I currently use both a Series 5 and Series 7 and both devices have had this issue. Both devices have lost their connection to my iPhone resulting in the need to unpair and add back.
The has been burning at no less than 25% an hour WITH low power mode on. What’s worse, when I put my series 7 on a charger, it continues to rapidly lose charge until it fully powers off. At that point it will finally start charging again.
Reddit has a few threads tracking the issue with some users claiming Apple uploaded a beta as the release version for some users. I’m not sure if that is realistic, but what I can say definitively is that this is the worst performing software update I have experienced.