I followed the ArchWiki article https://wiki.archlinux.org/title/Greetd

It supports various different greeters and I used agreety, recently I switched to qtgreet using Sway. I also needed to add some PAM configs so that it could automatically unlock kwallet and gnome-keyring.

I didn’t use auto-login but as you’ll see, there is section in the article that is dedicated to that.