Have you tried turning off HDR? The game gives that option.
Both my PC hardware and my smart TV support HDR but I never bother with it. There are so many versions of the HDR standard and often very poor compatibility between what the software and the hardware think are the right one.
As a non computery person, what settings am I looking at to get rid of these 'gradients' on sky / lighting sections when playing my Xbox on moniter?
Apologies for the poor photo, but think you can see them.
It's a 4k, hdmi 2.0 monitor with HDR10 if that helps?
Don't get them on anything work / video related, only on games.