Can't boot after update (no Qt platform plugin could be initialized)

After updating the system doesn’t boot, it’s stuck on a black screen and I can only access CLI.
Updating via CLI doesn’t work. I tried reinstalling both xcb-util-cursor and libxcb-cursor and it did nothing.

Please send your pacman.log to see which package was updated.

paste-cachyos /var/log/pacman.log

Any idea what could be wrong?

Are you not able to get this working? I believe there could be incomplete upgrades or version mismatches. Try running sudo pacman -Syyuu and see if that fixes it. If not, please send a new log from sudo cachyos-bugreport.sh

It’s still not working

Have you tried starting plasma manually via startplasma-wayland? It looks like you’re using an outdated Plasma theme, either splash or SDDM that’s causing it to fail to boot. Is that the case?

When I try I get an error:
Error: could not determine $DISPLAY.
ERROR: Can not contact kdeinit5!
org.kde.startup: “kdeinit5 shutdown” Qlist() exited with code 255
startplasma-wayland: Shutting down…
startplasmacompositor: Shutting down…
startplasmacompositor: Done.

Edit. After some tests I’ve found out that changing global theme to anything makes desktop turn black, starting it manually gives:
QPixmap: QGuiApplication must be created before calling defaultDepth()

Try running this

lookandfeeltool -a org.kde.breezedark.desktop```