Ironically, you are the one who needs to do more research.
I have deployed NAT64 in multiple networks before.
NAT64 is used when you have _internal_ IPv6 hosts who want to reach the _external_ IPv4 hosts. In order words, 2001:db8::1 can send something to 198.51.100.1 but not vice versa.
Your proposal is that we use IPv4 _internally_ since you think "internal IPv6 is overly complex" and we should "NAT to internal IPv4's". It doesn't exist since IPv4 is inherently forwards incompatible.
"HN doesn't understand the Internet Protocol" strikes again.
For your education:
https://en.m.wikipedia.org/wiki/NAT64