could not edit, but probably a lot of people did not understand my comment. our company often deals with very strict rules so that most services in the internet are blocked. we use gcp/gke with surge updates, thus we would loose our static access ip.

however now since they explictly need to enable our services we need a static ip and it is way easier to do that with nat gateway. basically we have a service that connects to http to their external ip which is firewall'd and thus if our client ip's will change it's a headache

No, NAT gateway for IPv6 does not make sense.