I am not a mobile dev :D I am aware that NAT is often used in corporate networks, but it does not automatically make any more sense there - the isolation is ac

I am not a mobile dev :D I am aware that NAT is often used in corporate networks, but it does not automatically make any more sense there - the isolation is achieved by the firewall, not by NAT. NAT (address or port translation) and a firewall (allowing traffic from/to those addresses or ports) are orthogonal concepts. You can do NAT on IPv6, if you so desire. It _should_ make no difference whether any adversary knows "what's behind a NAT", because it is your firewalls job to block any unwanted traffic. Relying on "nobody knows what is inside our network so it can't be attacked" is not a viable strategy.