sddm VS lightdm

Well, it seems it is still considered experimental https://github.com/sddm/sddm/pull/1737

There are dozens of threads everywhere about it since around early 2021. KDE will take over the SDDM project and that bug fix may soon finally be up-streamed.

LMAO the login issue was this https://github.com/sddm/sddm/issues/1592

Wayland autologin does not work with sddm (if you're using such a configuration) https://github.com/sddm/sddm/issues/1676

Thanks everyone for your time - installing xorg-minimal solved the issue; next version should solve the issue topic discussed in sddm github. I leave the following here just in case someone with skill & time comes across - seems a bit of love would not hurt sddm: https://github.com/sddm/sddm/issues/1471

Relevant to your keyboard configuration issue: https://github.com/sddm/sddm/issues/703

Also fixed in -git

No, the picture shows that the login manager is still sddm, but somehow the login theme used by sddm has been reverted to the sddm default of the 'maui' instead of the 'breeze' theme used by default in Kubuntu. The package shipping the breeze theme (sddm-theme-breeze) may have become uninstalled, or sddm config changed somehow to not use breeze.

That's why focusing on LightDM-KDE would have been the best course of action. Annoying bits developed somewhere else and the Plasma integration bits in-house.

I've said it in the past and I'm happy to repeat myself: The best option for Plasma is still LightDM with a custom greeter, just as it was common in the later Plasma 4 days when KDM was still the default but deprecated in the real world. So dusting off LightDM-KDE, picking up another Qt-based greeter such as https://github.com/firatakandere/lightdm-dynamic-greeter, or build one from scratch is certainly what should be done.