For anyone still looking for a solution to this issue:
- Go to the HDR section and find this slider, (at the very bottom of the screenshot) and adjust it all the way to the left.
This will make all screen captures appear as they should, but your overall OS brightness will appear fairly dark.
- This step is going to depend on your graphics card, so I can't give you specifics unless you have an nVidia card. Find your graphics card manufacturer settings and adjust your gamma until your brightness is as you like it. nVidia screenshot shown.
From 1 to 1.5 was enough for me.