Comment by MisterTea
For situations where you have no control over the NAT then this is indeed the case.
Though, 9front lets you run your own NAT giving you an Internet facing 9 machine you can serve a TLS tunnel from directly. So the server side is solved making the client side NAT a non issue.
If your 9front machine is in a position on the network whereby it could serve a NAT, you don't have many networking problems at that point. Almost all operating systems can do NAT in such a position.
I'm talking about two machines deep in somebody else's network or where you don't control the router/NAT.