At least Kubuntu can use our ‘
univention-domain-join’ if you choose to use it within a terminal. KDE uses a login manager that is currently not recognized but doesn’t need any configuration - it recognizes a domain setup and handles the login accordingly. So it is safe to just skip this step and configure the system to authenticate against a DC.
user@kubuntu:~$ sudo univention-domain-join-cli --skip-login-manager
You might try this with similar distros too but surely it won’t work with distros that use different methods to configure domain authentication.
For Debian you want use the manual method described in the Extended domain service documentation which is also explained here: