Apple Watch SE black screen?

Hi guys,

Just recently bought an Apple Watch SE and updated to the latest iOS.

Since then, my Apple Watch screen is often black - especially when I leave it on my nightstand at night. The only two ways to get out of the black screen is to charge it, or hard restart.

I haven't done anything unusual to it and use it only for the regular things: watch, phone calls, messaging and fitness.

The watch is still on as I can feel the Digital Crown clicking, and have accidentally set off an alarm whilst playing with it with the black screen.

Any ideas? Help! Apple Support in NL are really not helpful at all.