I plan on making/helping create the GUI once my Sony Xperia X stops sharing all my personal data and becomes more sailfish.

If you have sfdroid (community port) or an official Jolla device you should be able to install xserver xsdl (Android app)

That would take the place of the command "kwin_wayland --xwayland"
(Simply open the android app instead)

Then you can continue exporting the display var and run a X11 app.