I think you can argue that building things is an art in itself.

The word you are looking for is firewall not NAT.

NAT does not provide security whatsoever. If the NAT mapped your (internal IP, internal port) to a certain (external IP, external port) and you do not have a firewall enabled, everyone can reach your device by simply connecting to that (external IP, external port).

I haven’t seen routers that do not come with IPv6 firewalls enabled by default.