If i may, i had this same issue today, it’s certainly related to the update of QT6. Did OP do an update recently ? if so you need to run
sudo pacman -Syu
There were a few threads related to this issue since morning.
https://discuss.cachyos.org/t/help-needed-desktop-not-working-anymore/19032/1
This should fix your issue, as it did mine. if not maybe do a snapshot rollback with snapper and then proceed with a new update. The important part has to be that plasma-integration & plasma-workspace have to update alongside QT6.