How to scale DPI in Ubuntu VM?

I can scale DPI of Fedora 32 VM using gsettings set org.gnome.desktop.interface text-scaling-factor 0.75 but it doesn’t work in Ubuntu 20.04 VM. The official guide dpi-scaling doesn’t include support for Ubuntu without GNOME.
Updating scaling factor in gnome-tweaks in Ubuntu doesn’t work too.

2 possible solutions:

a) set Xft.dpi in Xresources
b) install ‘gnome-settings-daemon’

Both will solve your problem.

Both don’t work for me.

Xresources

$ xrdb -query -all
Xft.antialias:	1
Xft.hinting:	1
Xft.rgba:	rgb
Xft.hintstyle:	hintslight
Xft.lcdfilter:	lcddefault
Xft.dpi:	200 # previous is 100

gnome-settings-daemon

$ sudo dpkg --configure gnome-settings-daemon
dpkg: error processing package gnome-settings-daemon (--configure):
 package gnome-settings-daemon is already installed and configured
Errors were encountered while processing:
 gnome-settings-daemon

Hm, I used the Ubuntu templates before and the Xft.dpi setting worked. But I didn’t have gnome-settings-daemon installed. Maybe remove it?

Are you building the Ubuntu template yourself or using the one from @unman? Or is this a HVM installed straight from the ISO without qubes packages?

I built Ubuntu according to Guide to installing Qbuntu (Ubuntu 20.04 - Focal Fossa) TemplateVM in Qubes Release 4.0.4-rc1, it isn’t HVM.