No display on iwatch

One thing to check: go to the Settings app on your Apple Watch, go to Display & Brightness, then make sure "Wake on Wrist Raise" is set to "on". Or scroll down to "Always On" and make sure that's set, if that's how you want your Watch to behave.

Hope this helps.

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

If this does not help, unpairing and connecting it again to your iPhone without using the latest backup would be the next step:

Unpair and erase your Apple Watch - Apple Support

Set up your Apple Watch - Apple Support

Did you already update your watch to watchOS 11.0.1 ?

You‘re welcome 🙂

Enjoy your Apple Watch again!