watch os 10.1 battery drain issue

If the battery drains too fast after an update, see all the replies to:

has anyone had battery issues with the 10… - Apple Community

Battery Drain since watchos 7.4 - Apple Community

WatchOS 7.5 battery drain - Apple Community

FWIW, in some cases, unpairing the watch, completely erasing it, then pairing and restoring the backup will resolve the battery draining issue after an update. (Simply unpairing and pairing again may not work.)

Unpair and erase your Apple Watch - Apple Support

Also, some people have found that simply waiting a few days after an update resolves the battery draining problem.

Also see:

Apple Watch battery drain - the ultimate … - Apple Community