> It’s the same assumption is required for any hole punching handshake (including STUN).

This is incorrect.

Hole punching requires being able to predict external port. That's it. If the port remains the same, it certainly simplifies things, but ports going up (or down) by 1 (or 2, or 5) with each new mapping is quite common, trivial to detect and to punch through.

I wonder how many new technical terms are going to be created by LLMs - not to say that this post was N necessarily written by an LLM (but, who knows!)