I have the same problem, and I’m using SDDM. My autologin.conf got deleted, so I figured it was a matter of restoring that, but no dice so far.
Edit: Ah, never mind. I forgot that autorun.conf is replaced by this kde-settings file there. Changed plasmawayland to plasma, there, and it started working.
Were you using SDDM for auto login? And wayland or X11?
Idk what I was using, I was using System Settings.
Wayland.
I have the same problem, and I’m using SDDM. My autologin.conf got deleted, so I figured it was a matter of restoring that, but no dice so far.
Edit: Ah, never mind. I forgot that autorun.conf is replaced by this kde-settings file there. Changed plasmawayland to plasma, there, and it started working.