> So here's a question: if your ipv6 is behind CGNAT and calls an ipv6 on the other side of the CGNAT: is it still one-way, or un-NAT'ed?
Depends, it's easy to do things like 464xlat and NAT64 where you route those address spaces through the CGNAT and other stuff direct. Or through a stateful firewall (which could be the CGNAT or something else) if you really need a stateful firewall.
IPv6 clients would not go through a CGNAT (or any other NAT) to connect to a remote IPv6 address. Including on Starlink.
Exceptions are so unusual you should provide a specific example of an ISP with this configuration.
So here's a question: if your ipv6 is behind CGNAT and calls an ipv6 on the other side of the CGNAT: is it still one-way, or un-NAT'ed?
And you agree the non-oligarch internet is ipv4, along with a large part of the oligarch internet.