Description of the issue (screenshots if relevant):
On two occasions when I’ve waked from sleep I’ve had to restart KDE because the panel, desktop background and desktop icons had disappeared. Running systemctl --user restart plasma-plasmashell.service worked at getting everything back.
Open apps are still visible. I already had Konsole open so I am not sure if opening Konsole with the keyboard shortcut will work in order to run that command. Dropping to a TTY would work though.
Relevant informations (hardware involved, software version, logs or output…):
Hmm, sounds like an upstream problem, maybe try to report to KDE directly. But first, make sure you are using the latest updates. If you are on KDE 5, ROME 6 will drop in a few days and might resolve the problem by bringing final fixes. However, if the problem is still persistent, then once you have updated to ROME 6.0 you can install plasma 6 and uninstall plasma 5. Plasma 6 is much better than 5 with a lot of work put into bug fixes and backend improvement.
This could also be a problem with drivers, your hardware or X11/Wayland. Which one are you using?