Try:
sudo dnf remove task-plasma6-* ; sudo dnf in task-plasma-minimal task-plasma-wayland task-plasma-x11
There is no need to use “plasma6”.
If that doesn’t work, do the following at your own risk as this will upgrade you to the latest version of Rome which has not been released yet (I am running it without any real issues).
sudo dnf clean all ; sudo dnf dsync --allowerasing 2>&1| tee dsync-log.txt
You may need to re-run:
sudo dnf remove task-plasma6-* ; sudo dnf in task-plasma-minimal task-plasma-wayland task-plasma-x11
More info here on the upgrade: