@ihasama ,
@Rosika and I did this together some time ago
Look at the section “Preparing virt-manager to support X11”
There are some Hardware settings required in virt-manager for X11.
I am not sure these will help with resolution… Neither @Rosika nor I had a problem with resolution.
but
Putting the user in the video group might help., and there are extra packages utouch-kmod and xf86-input-evdev required.
Also see the next section on installing Xfce
I had a quick look at my FreeBSD in vier-manager. In Xfce the display is 1280 x 720… that is more than VGA.
My video setting is XQL.
My Display is set to Spice Server.
Regards
Neville