i can't speak specifically to Wasabi, however, with JoinMarket you retain the wallet's private keys on your machine at all times.

If it goes offline, is the Bitcoin lost? For example, wasabi wallet depends on their centralized server.

JustinNakamoto

https://bisq.network

https://hodlhodl.com

https://learn.robosats.com

https://agoradesk.com

coinjoin is simply a collaborative spend.  i'd say it's difficult to stop people from collaborating.  if you're worried about a particular open-source codebase being pulled, remember the code can be forked and republished by anyone.  new coordinators can and will arise as information wants to be free.

bitcoin

Lighting Network Privacy

JustSomePleb

Bisq - https://bisq.network
Hodl Hodl - https://hodlhodl.com
RoboSats - https://learn.robosats.com
Agora Desk - https://agoradesk.com

coinjoin is simply a collaborative spend.  i'd say it's difficult to stop people from collaborating.  if you're worried about a particular open-source codebase being pulled, remember the code can be forked and republished by anyone.  new coordinators can and will arise as information wants to be free.