Thanks for bringing this up. I have a 1080p portable monitor (and it was expensive because it's a Sidetrak Swivel that attaches to the back of the laptop).
I was just looking at some reddit posts about scaling for multiple screens, and it sounds pretty shaky in Linux, and more so in KDE. I definitely don't want to go back to gnome in Linux haha, but apparently I might need to give wayland a try.