First I open ‘shutdown panel’ to show it opens. Then I update the system (because I restored from snapshot, there is a pacman lock. Removed it.) Then I try to open the ‘shutdown panel’ again and it is just dark screen. Then I switch to TTY3 and reboot. Now theme is broken. Logging in with Wayland, it doesn’t do anything. Logging in with X11, it starts autostart apps but can’t move the application or do Alt+F3. Then I try Ctrl+Alt+Del (opens ‘shutdown panel’) and it’s just black screen. That’s all of the symptoms I could find.
file:///usr/share/sddm/themes/breath2/main.qml12:1 plugin cannot be loaded for module “org.kde.plasma.core”: Cannot load library /usr/lib/qt/qml/org/kde/plasma/core/libcorebingingsplugin.so: (/usr/lib//ibKF5KIOcore.so.5 undefined symbol: _Z...)
that way, you basically locked your system on the old version as stuff inside your home always has a higher priority then stuff in /usr, but the stuff inside your home does not get updated. That would equal a partial update.
Undo that and check if the issue still happens.
This has also been happening to me for a few months! For a while downgrading the plasma-framework package would fix it, but after plasma 6 was released that stopped fixing it. I’ve switched over to gnome since then, but now I’m thinking it’s time for another fresh install of endeavour
I found the solution a few days ago. It was because the karchive-git package. Switched it and everything related to it to normal releases and that was the solution. Maintainer for that package made some changes about Qt versions so that was the reason. Not sure if it would be the solution for you.