Nice trick. Just a heads up that I had to whitelist your domain as NextDNS blocked it for being newly registered.

Given this thread will probably attract other Unifi users... has anyone had success migrating from MongoDB to something like FerretDB?

I played around with getting this to work a few weeks ago and found that day-to-day it works without issue, but restoring a backup will error since it relies on some unsupported Mongo semantics (renaming collections iirc).