This is that and you are right. Nvidia is not really ready for Linux Highend Gaming. BAD DX12 Performance. Linux Gaming without Auto-HDR out of the Box experience is missing. Linux HDR Desktop no contrast control on nvidia gpus and bad HDR Linux Desktop Colors. It looks like washed out. I have compared with my mini PC how has Ryzen AI GPU and i must say, It looks so different, the desktop and the colors are an another level.
Have a Nvidia gpu and it works fine. The DX12 performance is not there yet but they are working on it and know what the problem is.
Do you not have contrast controls on your monitor? I thought every monitor in existence has contrast and brightness controls. If the colors look over exposed you probably don’t have the vulkan HDR layer installed. This is a known issue with Nvidia gpus because Nvidia has not added the vulkan extensions yet to pass the HDR metadata. If you have KDE Plasma, it inverse tone maps everything: desktop, games, ect.. It might not be as good as Nvidia’s implementation on Windows but good enough in my opinion.