I’m using EndeavourOS with KDE.
The display is correctly oriented when logged in but it doesn’t rotate correctly when I’m logged out.
EDIT: corrected the post. This happens when logged out, locking the screen has it displayed correctly.
Put one hand on the top and one on bottom and rotate the screen by 90° or π/2 radians
If you have to read PDFs regularly having a vertical monitor is a lifesaver.
You could use Windows 11 from Microsoft, it can do both landscape and portrait.
It’s true though, every thread about Windows is full of Linux users saying how you should just use Linux, and others saying they still can’t because it still doesn’t work properly after all this time. Then you get the Linux users saying “iT jUSt wORks”, then posting shit like this demonstrating that it clearly still doesn’t