Just listening to the optech recap podcast 355, fyi nostr:npub1syluunzwwmc70d85d9alzqc2jrc6pdur7xrax2vqpfxas6tljavsa46ksu, joinmarket has a server to coordinate the coinjoin: the taker, the nuance is that there is an open market for who can run this server.
The only truly decentralized coinjoin protocol is coinshuffle (++), but it's very complex and I think was never implemented.