I have this as well, but run a heavily locked down and isolated BIND server with NSD and Unbound for external authoritative and internal caching DNS respectively.

Its easy to feed an RBL to unbound to do pi-hole type work, I use pf to transparently redirect all external DNS requests to my local unbound server but I get the bind automation around things like DNSSEC, DHCP ddns and ACME cert renewals.

I'm surprised this isn't a more common stack.