sddm.service, et al, were installed during the general Plasma Workspaces group install, but switching to it as the login manager doesn’t do the business for me.
I’m not seeing a way out of the Classic GNOME Desktop thing at the SDDM login prompt. There’s no gear to select from, and I have no Gnome-related environment variables in my .bash_profile or bashrc files. There is a file, /etc/environment, but it is empty.
I don’t know what more I can say at this point. I know that there are some sddm-related config files, but I’ve left them at their defaults for now.
Ack! I didn’t notice before doing one more login with sddm as the graphical login mechanism, that you can actually make a selection on the page. It’s in the lower left corner of the page where the options “Classic GNOME…” sat. It turned out to be a selectable menu.
Et voila! Magic happened, and all the problems I was having were resolved.
Egad this affair does not make me feel good about my detective skills.
Thanks again for hanging with me though this process!