Apple Watch 6 dies after 8 hours

Over the last three days my Apple Watch 6 is dying after 8 hours. I’m not doing anything different to normal, and I have tried reducing things that might affect the battery by switching off various features. It’s not even a year old I got it for Christmas 2020.

it’s dead at the moment AGAIN but when it charges up I’m going to try pairing and unpairing. Any other advice?