NAT doesn’t improve security if port numbers are easy to guess, which is usually the case.
If you wanna block inbound connections, just drop them with your firewall. Most home routers already do this by default and if yours doesn’t, you better enable it for IPv4 too.
If you wanna block inbound connections, just drop them with your firewall. Most home routers already do this by default and if yours doesn’t, you better enable it for IPv4 too.