Primary screen not working after wake from sleep (only KDE 5.26)

[omano]

I had similar issue with my main monitor on Nvidia Display Port and latest KDE, the solution is in this post as a workaround

KDE plasma bugs after each update [Stable Update] 2022-09-12

Folks, I have some good news. Thanks to the Upper Grandmaster of the Secret Order of the Manjaruminati, @philm, those of us who chose to skip the update from Plasma 5.24.6 to Plasma 5.25.5 now have the ability to install the updated Plasma 5.24.7 LTS. @philm was so kind as to build the packages on the GitHub server and to make them available here. So if you’ve skipped the upgrade from 5.24.6 to 5.25.5 but you want to upgrade to the newest 5.24.7 LTS, then here’s what y…

//EDIT: do a sudo pacman -Syyuu when done to be able to downgrade, then reboot. Also do a system backup before proceeding to the downgrade, so you can get back on your feet if something goes wrong (TimeShift or whatever backup solution you use).