I had this too. My fix was lowering black saturation on my monitor. It was previously to that absurdly dark. based on conversations with others this problem seems more commonplace on higher quality peripherals. A simple gamma scaler would be nice but until then hopefully this helps.

Nvidia settings?

Keep in mind: Nights and dungeons are supposed to be dark. But I know the difference between dark and dark... I've seen this in many game myself.

Just start the game and force the brightness on the fly with you GPU software to see what suits you best.

Torch or a later game object may be helpful too. ...and in dungeon - leave the yellow mushrooms until you're heading back to the entrance.