On Kubuntu 19.10, snap apps install here:
/var/lib/snapd/desktop/applications
To fix UI scaling, I just add the following flag to each of the .desktop
files for Electron apps in that folder
--force-device-scale-factor=1.2
before %U
and this seems to work well for making the UI about 20% larger, which fixes the issues that I had been having on my 1080p screen on a 13" laptop