Don't implement yourself, use the actual SimpleX client and server. "Each relay becomes a SimpleX server" means the relay and server are on the same host, different ports. The server may need some modification to allow for the discovery process I'm proposing.

SimpleX seems to be well maintained according to the commit log, just the .js isn't.

"We're sacrificing almost all the values we stand for because it's all we could do in 100 lines" isn't a great message.