[CentOS] Trying again: KDE fails with a gray screen after login, can't reinstall

I set for graphical mode, I get the login screen, I change to KDE, and the screen goes black, then after minutes, gray with a cursor, and that's it - I left it overnight, no change.

Brand new install (as of yesterday). Missed any "agree to license", and missed choosing software. Manually groupinstalled Installed Environment Groups: KDE Plasma Workspaces Development and Creative Workstation

Tried to reinstall: No group named KDE Plasma Workspaces exists

I'm assuming I need to install something else, but does anyone have a clue? I really do NOT want gnome.

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