6900xt is working very well on 8Kx.
You should probable look at this:
I have not added AMD FidelityFX (FFX) yet.
In DCS I am flying UH-1H, so I need to be near the ground. I still get 90fps with good resolution. I do not want to go confirm what resolution i am using at this point.
Project Cars 2 90FPS mostly max game settings (one or two cars).