My Apple Watch, series 7, has always been set to Wake on Wrist Raise, and has always worked fine, until I installed Watch OS 11.0. Now, everything is still set the same, but nothing happens when I raise my wrist. I have to tap the screen or turn the crown to see anything. (The screen is also set to always be on, but that has never worked.)
This happened to me as well. Using the Watch app → Display & Brightness → Wake on Wrist Raise I toggled the setting Off, paused a second or five, the toggled it back on.