The link to the bug report ends in “no results found”. Maybe it is already fixed (but not pushed out yet)?.
Anyway, stumbled over the same issue a few minutes ago and reverted with sudo pacman -U /var/cache/pacman/pkg/qt6-declarative-6.11.0-1-x86_64.pkg.tar.zst
to the old pre 6.11.0-2 version for the moment.
Edit: and qt6-declarative-6.11.0-3 is available and fixed the issue.
Had to reboot.
Logout and back in from or restart Plasma may also work but don’t know. Without the logout button in the launcher the reboot command was the first, and therefore the easiest, thing that came to mind.
Just checked “Control-Alt-Delete” and go from there may have worked, but I managed it without