I'm plugged in with a high speed HDMI right into my GPU
My aspect ratio on kde display settings is 16:9, resolution 3640x2160
I've played in 4k on this machine before with these games, but that was before I reinstalled a couple weeks ago to fix a different problem (mostly Helldivers 2, DOOM 2016, and CoD WWII)
I ran
paru -Syyu amdgpu
I could be missing something though theoretically I'm not out to say I know everything
http://aaronhoyt.com/gfy.asp