I've implemented powerdns in prod a few times and really like it. There are some quirks but it has good documentation and a huge point for me is it is gpl (or gpl compat, I can't remember which)
Same, I use it as the central authoritative DNS server for our internal domains, backed by a simple sqlite datbase which seems to be able to handle it without a single issue. Local Bind9 instances are configured on all our sites to ASFR all zones, and handle the client-facing traffic. All this is managed using Ansible, and works like a charm.