Start an application as root from menu

After upgrading to Plasma 6, I cannot any more start from KDE menu an application as root.
I used that way to start as root krusader, but also my script (to sync with rsync or rclone other devices): that is, in menu editor I set advanced → rus as a different user → root. And so far all was ok.
After upgrading at the beginning I managed to use successfully this argument env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY KDE_SESSION_VERSION=5 KDE_FULL_SESSION=true
, but now (since yesterday) neither this workaround works any more.

I reported this as a bug, and someone added qt6 as keyword.

Any suggestion?

EDIT

I tried unsuccessfully to add kdesu in /usr/lib/x86_64-linux-gnu/libexec/kf5/, and make it executable.
Likewise I tried unsuccessfully to create the group wheel, and to add my user to it.
Nothing to do.