If they make it illegal people will be forced to buy, sell, and transact outside of kyc services. This is why building circular economies and supporting/using services like bisq, robosats, peach, and hodlhodl is so important.

I don’t know that you can make any other txn look like a collaborative txn, BUT we can make all or most txn look like a collaborative txn. If a jurisdiction makes collaborative txns illegal then people can move to a friendlier jurisdiction. But enforcing these these types of laws is impractical at best.

In Roman’s case I don’t think they arrested him because he was using bitcoin fog to mixi his coins, but because authorities think he was laundering money.

Taproot adoption should help with this?

I think what's most likely is that the governments will ban accepting BTC if it didn't come from KYC. So all the people currently coinjoining for privacy will be locked out of legally spending, and their mixed coins will not be accepted at fiat offramps. They are locked into the circular economy, for good or bad.

I think all bitcoiners should brace themselves mentally for this possibility on a very personal level. The assumption must be that no-one will be there for you if this happens. The principles of privacy and self-sovereignty are meaningful enough to go to prison for if push comes to shove.