I worked in software certification under Common Criteria, and while I do know that it creates a lot of work, there were cases where security has been improved measurably - in the hardware department, it even happened that a developer / manufacturer had a breach that affected almost the whole company really badly (design files etc stolen by a probably state sponsored attacker), but not the CC certified part because the attackers used a vector of attack that was caught there and rectified.
It seemingly was not fixed everywhere for whatever reason… but it’s not that CC certification is just some academic exercise that gives you nothing but a lot of work.
Is it the right approach for every product? Probably not because of the huge overhead power certified version. But for important pillars of a security model, it makes sense in my opinion.
Though it needs to be said that the scheme under which I certified is very thorough and strict, so YMMV.
I have full IPv6, none of my ports that I haven’t explicitly whitelisted in the firewall can be accessed from the Internet. I can open a host completely, but it’s not default. This is on the most common brand of consumer routers here.
Just because it’s not NATted doesn’t mean there’s no firewall in place.