I’ve been happy with AdGuard Home on two Pi4s and a little home server for years now: https://adguard.com/en/adguard-home/overview.html

I have some scripts to sync config between them and a Jenkins job if I want to pause blocking on them for a bit.

It looks like https://github.com/mattwebbio/orbital-sync and https://github.com/lovelaze/nebula-sync can sync configs with Pi-hole 6 now, but it’s quite a bit of code for what looks like just a few HTTP requests to get the config from one using the teleporter feature, then restore it on the others using the same.