all, first time poster, I work on iroh, a UDP-based holepunching library built on QUIC: GitHub - n0-computer/iroh: IP addresses break, dial keys instead. Modular networking stack in Rust. · GitHub
Iroh has a 90%+ holepunching rate, and 99%+ connection rate, but uses federated relays similar to a webRTC STUN & TURN servers to achieve these numbers, which I’m assuming is not entirely appropriate for bitcoin. With that said, we’ve spent a lot of time on the topic, Including integrating with TOR, encrypting the exchange of candidate addresses, and employing novel techniques for holepunching itself.
ill keep an eye on this thread & can try to pull in experience & figures where useful!