It's Friday 10th December 2021 and I had exactly the same problem.
I was trying to play Fallout 4 and I originally thought it was the NVIDIA GeForce Drivers playing up at first. I originally thought it was something to do with Windows 11 and then found this forum feed.
After digging through Device Manager, I realised it wasn't detecting the NVIDIA Card at all in my Surface Book 3.
I tried reinstalling the Firmware / updating it - and that didn't work.
However, I detached the screen - immediately reattached and it and BOOM it was back.
I think the bug comes from something to do with Sleep mode. I never use Sleep mode, but I did for the first time yesterday and for some reason, it doesn't wake up the NVIDIA Card or something.
I hope this helps you!
THANK YOU to everyone for all your great posts here. I was going nuts without Fallout 4, but appreciate you sharing your stories.
As much as I love Microsoft, they need to fix this. It's $3k laptop, and whislt I love the laptop - bugs like this make it hard for everyone.
THANK YOU ALL!!!!!!!!!!