Wrist temperature don’t measure when I sleep on Apple Watch Ultra 2

Do you have a Sleep Schedule enabled and allowed the Sleep app to use the watch to track sleep and temperature?

Track your nightly wrist temperature changes with Apple Watch - Apple Support

Do you have another Focus mode active during or before your Sleep Schedule, for example Do Not Disturb?

Did you try to force restart your watch by pressing and holding the Digital Crown and the Side button together for about 10sec, until the Apple logo comes back again?

Also force restart your iPhone:

Force restart iPhone - Apple Support

You should contact the official Apple Support about that, they can diagnose your watch online, to find a reason for that. As a user, you have tried all the recommended troubleshooting steps.

Contact Apple for support and service - Apple Support

Yes, if the Force Restart did not work, unpairing the watch would be the next step:

Unpair and erase your Apple Watch - Apple Support

Does anything on this garbage watch work normally?

the Ultra 2 I have does nothing good, 700 euro in the toilet and now I have a watch that does nothing….

apple just do updates for chatGTP and Tesla and that’s it. Other things don’t matter people just buy it and get scammed