Iphone 16 apple watch 10 backup corrupted?
Watch 10 when connected to an Iphone 16 has the battery in ultra rapid drain
Apple Watch Series 10, watchOS 26
Unpairing and pairing the Apple Watch again has helped other users.
Unpair and erase your Apple Watch - Apple Support
And, to rule out defective data from the backup, set up the watch as a new device after that.
You will only lose your created Watch faces and may have to activate the cards in your Wallet app again.