My Qubes 4.0, cpu AM3 X6, graphics Rx560 is connected to a Sony 4k tv and working fine :-)
Is that what you want to know?
Im using a 15 inch screen, on 3.2 qubes did and was not able to scale menu icons and other smaller objects.
some objects were scaled but many not,
does 4.0 scale EVERYTHING , all icons... ?
Using high resolution tv (4k=3840x2160 pixels) and everything is fine, but fhd tv (1920x1080) needs to adjust dpi settings in each vm (gnome-tweak-tool) you use.
I only have a 15 inch screen and will not use a TV.
the 15 inch screen has 4k resolution.
gnome tweak tools did not work properly at 3.2, does it work perfectly at 4.0?
Sorry. We had different experiences.