The real issue is the centralized coordination service who takes a fee.  JoinMarket could work, but I still think the future is #PayJoin.

Normalize building PayJoin into typical spending patterns which has no distinct on-chain fingerprint, and which can result in reduced tx fees (afaik).  Break the heuristics, improve everyone’s plausible deniability. 

 The fee was actually novel. It served both as one of the few sustainable revenue sources for open source development but also functioned as an anti sybil attack mechanism. The fee was a benefit to devs and users.  

 That may be, but it sure does highlight the central point of failure, and paint an easy target for regulators.