Same here, with a new 3080 FTW3 Ultra.
Spent the whole day yesterday of gaming and browsing without problems, then when the desktop was just sitting there with a single browser window, it went black.
Things were still running in the background, because sound was also still there. Tried Win+ctrl+shift+B, but did not bring back the screen. Had to hard reset it. After that its everything normal again.
The event viewer says, that the driver stopped respondig, but has recovered. But obviously the HDMI display output didnt.
Using an LG B8 OLED at 4K60, no gsync.
Would be nice if someone figures out this. Isnt funny with an 800$ card. I hope its just the driver, and an update very soon solves this.