Is your feature request related to a problem? Please describe.
Currently there is only support for creating virtual displays with legacy intel driver.

Describe the solution you'd like
Using evdi kernel module it's possible to create a driver-independent virtual display.
I found it at https://unix.stackexchange.com/a/585078 (for me steps 3 and 4 were not needed, but also I couldn't make more than one virtual display).

The problems with this solution:

• it requires manual kernel module installation.
• If kernel module is loaded while Xorg is running, then Xorg freezes.

Describe alternatives you've considered

• intel driver is obsolete
• having screen resized with xrandr --fb is not good enough, because you can't for example make a window go "full screen" there.
• https://wiki.archlinux.org/index.php/Extreme_Multihead#VNC says xorg dummy driver is not good for hot plugging monitors.