I'm trying to switch from ubuntu gnome to kde on an intel laptop., I've installed kde-standard but on reboot, the login hangs. I can select a user, enter password, etc. but then nothing happens. A terminal login via F2 allows me to switch back to gdm3 and log back into gnome. Something, SDDM, must be mis-configured? I've used dpkg-reconfigure to switch back and forth, SDDM consistently hangs. I've not used sddm before and configuration/trouble shooting advice would be appreciated.
Incidentally, I recently did the same conversion process on an intel NUC with no problem.

Linux oak 5.13.0-28-generic #31-Ubuntu SMP