Depending on what exactly you mean by "Un-KYC", CoinJoin or mixer may works for your use case. But,
1. It's easy to detect CoinJoin TX, where some centralized exchange/service doesn't accept coinjoined Bitcoin.
2. You need to trust mixer.
3. Some mixer give you "tainted" Bitcoin, which also not accepted by centralized/service.
You can also use private exchanges, like those suggested in
kycnot.me, at least for one of the Bitcoin <-> privacy coin exchanges.
Just don't forget you still need to trust many of the listed exchange and the fact they usually have worse fee/exchange rate.