Primary Display Changes After Waking from Sleep

After changing secondary display (now HP Z27i, WQHD) and switching to Wayland, it always happens that the largest monitor (32" Iiyama, UHD), which is supposed to be set as primary, loses its status. There is no more way to to define a primary display in KDE system settings. The only way to restore the configuration is to logout and logon again, which is a hassle.
If I choose to turn off the smallest monitor, the session is locked, forcing me to run

$ loginctl unlock-session 2

Has anybody solved this issue so far? Thanks for your support.

Try completely resetting your Display and Monitor settings from scratch.

First logout of your Plasma session.

Then switch to an unused TTY (i.e, CTRL + ALT + F3), login as your user in the console, and then rename the current display settings folder:

mv -v $HOME/.local/share/kscreen $HOME/.local/share/kscreen.bak

Exit with CTRL + D.

Now log back into your Plasma session on TTY1 via CTRL + ALT + F1

See if you can reconfigure your Display settings properly, and if your primary display will “stick” upon resuming from suspend.

Hi winnie, thanks for your advice.
Anyway, this is what I get after kscreen reset:

Pic resolution gives a hint: Taskbar on supposedly secondary display :frowning_face: