Fuckin hell! That's impressive though as long as it works, but the lengths we go to avoid opening a port is crazy, meanwhile Bittorrent have been using upnp like there is no tomorrow!
There is still the problem of discovery (when suddenly I don't have common relays with the nsecbunker service provider for some reason).
Using Nostr as a replacement for good old web platforms instead of decentralized DNS (Pkarr) and opening port when necessary, sounds as extreme as using p2p stack and holepunching, just more browser friendly.