Recently updated my Apple Watch 6 OS to version 10.1. Since then my watch battery has been draining fast, It was on full charge this morning and not it says 10% battery left at 2:27 PM PST. Normally by 7pm I still have decent 45-50% left. I’m at work and don’t use the watch actively. Just let is on my wrist and go about my day. I only checked my heart rate twice
This has happened to me with previous updates (not this one, though). Try unpairing from your phone and repairing. That has worked for me.