Samba upstream package does not provide the DC role, by now.
@giacomo and @mark_nl already answered, I just want to add: Samba itself suggests keeping the file server / domain controller roles on separate servers.
Whilst the Domain Controller seems capable of running as a full file server, it is suggested that organisations run a distinct file server to allow upgrades of each without disrupting the other
Moreover, I must admit it simplified a lot the configuration both on the file server side (the “host” machine) and the domain controller side (the “guest” machine/container).
So I’m sure an additional IP address is a small price to pay for having them both on NS7 