True, but according to their other thread that they started at the same time they posted here, see: Rocky Linux 10.1 and Desktop Environments of which you’ve replied to already - they made a clean install. So, at that point it’s a case of whether you want Mate or you want KDE.
It’s probably easier to install the system from Skip’s Mate ISO and then add KDE, rather than the other way around - at least going by the fact they’ve had issues with that and posted about it here.
Had the system been in use for a long time, then it’d make sense to find a solution for it. But if it’s a clean install, probably quicker to reinstall than diagnose the issues.