"I was just on ex-birdapp and there was a legit discussion about how coinjoin/collaborative transactions make you vulnerable."
I'll be devil's advocate and state that I get this argument somewhat; if you compare it to browser fingerprinting, the more you stand out protecting your privacy (since the majority don't), the easier it is to track you.
In theory, that makes sense. In actuality, however, that argument is rendered moot when you use an extension like CanvasBlocker on top of your privacy-preserving ones to change the fingerprint every session.
Same goes for CoinJoin and collaborative transactions; if you use them a lot, or all the time, you'll never be tracked if you combine that with good wallet transaction practices.