Watch Ultra battery

You're welcome.

Another thing to consider is the new Optimized Charge Limit on your Apple Watch Ultra. The Ultra watches have a more advanced battery management system. It takes about a month for the watch to learn from your daily wear patterns. And its designed to charge your watch up to the level you'll need for the day as opposed to charging fully to 100% every day. This may or may not be what you're seeing as well.

While not an Apple Support article, I found this tutorial on Optimized Charge Limit for Apple Watch Ultra, very informative --> https://appletoolbox.com/how-to-use-optimized-charge-limit-on-apple-watch-ultra/

Restart your watch, which will close any open applications in the process.

Hold the power button until the SOS screen appears

Upper right see round shutdown button and tap it

Confirm shutdown and wait 30 seconds

Hold the power button again to turn the watch back on (you'll see the Apple Logo), then sign in