Comment 8 for bug 1693418

The smb.conf snippet from comment #7 is very different from the SMBConf.txt attachment to this bug. Comment #7's is an AD controller, whereas the attachment is for a standalone server. This changes things.

That being said, this seems to be the issue:
Mai 30 07:59:49 pdc smbd[7719]: You should start 'samba' instead, and it will control starting smbd if required

When using samba as an AD controller, you have to use a different systemd job. Run the following:

sudo systemctl mask smbd.service
sudo systemctl mask nmbd.service
sudo systemctl unmask samba-ad-dc.service

Then try "sudo apt -f install" or "sudo dpkg --configure -a".

You may have to start samba-ad-dc explicitly:

sudo systemctl start samba-ad-dc.service

The error log message is a bit misleading, talking about a "samba" service. It looks like samba-ad-dc replaces it.