Old stuff won't work, but these new protocols and IPv6 should do just fine.

Works fine for Keet and Holesail, so seems like it must

Oh yea I suppose Syncthing (which works for mobile) must be doing hole-punching as well and it works swimmingly

Yup, NAT holepunching is working good on mobile devices (iOS and Android both), in fact I have used holesail to access my Windows VNC on mobile

Hey! Very glad to learn you're on Nostr. I work on solid state interpreter personal servers, and hole-punching is a task we'll be looking into very soon as we get deeper into peer-to-peer aspects.