This is a follow-up to this post where @megavolt said that enabling Xinerama will enable KDE to treat two screens as one.
I have the same monitor as @kansas.manjar0 (LG Ultrafine 5k), and even have Xinerama enabled in Clear Linux:
$ xdpyinfo -ext XINERAMA | tail -2
XINERAMA version 1.1 opcode: 140
head #0: 5120x2880 @ 0,0
But KDE doesn’t recognize this has one unified screen. Does anyone know how I can diagnose this further?