Not trying to be a smartass, but managing DNS at scale IS a solved problem. Mayb...

NoZebra120vClip · on Jan 28, 2024

Speaking of managing at scale and splitting well:

  the reverse lookup domain name corresponding to the address

       4321:0:1:2:3:4:567:89ab

   would be

   b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6.
                                                                  ARPA.

https://datatracker.ietf.org/doc/html/rfc3596#section-2.5