There is ongoing W3C work on a protocol called WebTransport which allows JavaScript clients to initiate connections which are QUIC-like, over UDP, benefit from avoiding head-of-line-blocking, are multiplexed, still have transport and congestion control, etc. It's mainly for low-latency applications like streaming, video conferencing, and MMORPG like browser games.
But I don't think latency rises to the level of a serious concern. You can do nostr-over-anything though if you want, the world is your oyster. But to me, this isn't one of our biggest issues.

