No distro GUI (KDE) when running prime-select in nvidia or on-demand modes

After choosing either nvidia or on-demand in prime-select the KDE interface
stops being rendered and appears as a black screen. However, all applications work
and will appear on said black screen. Moreover, after setting env variables
nvidia card starts being used by applications.

Please run as root and attach the resulting nvidia-bug-report.log.gz file to your post.

Thanks for quick reply!
Meanwhile, I uninstalled Displaylink Manager, thinking it might be to blame. This caused Xorg server to crash on every boot for some reason. So I went for it and installed pop_OS. Now I can seamlessly switch between nvidia-prime modes.