What brand of 3080 are you using? Hopefully its not a Gigabyte.
But chances are, the game is pushing the card enough for its flaws to manifest. This has been occurring sporadically since launch with a few people.
And many were Gigabyte cards, which are known to have defects that might present under certain load conditions.
Not saying that Diablo IV is completely innocent either. I mean the graphic engine seems to need some better optimizing, or something.
Its better than it was in beta, but still quite taxing on hardware.
More threads with the same thing:
https://us.forums.blizzard.com/en/d4/t/diablo-4-server-slam-cooked-my-gpu/21857