SDDM not showing users
Only the installation (local) user is displayed at the login screen.
My documentation suggests, that it might help to add the network as a dependency to the sddm.service
SDDM/Login-Manager
In the case that KDE’s default login manager SDDM does not show any accounts to select for logging in, the following might help: Copy sddm.service from /lib/systemd/system to /etc/systemd/system, and add a line After=network.target to the [Unit] section.
Implement it as part of the ipa-hosts role.