Yep, which is actually specifically what tornado.cash was.
It was a zk based mixer.
As you say: You absolutely CAN seamlessly mix crypto, but it will show a point in it's history where it says "this is where the crypto was seamlessly mixed"
As you say: You absolutely CAN seamlessly mix crypto, but it will show a point in it's history where it says "this is where the crypto was seamlessly mixed"