I think the closest thing is Atomic Swaps.  All the other currently existing alternatives are now closed source or honeypots.  Wasabi turned bad, Samourai was weird already.  What is left is using Bisq to enhance privacy or ChipMixer but Bisq is an exchange and ChipMixer is mostly trust based.

I imagine the open source Monero to Bitcoin Atomic Swap mechanism will be very handy for privacy.  Move Bitcoin to Monero and back and you have a new set of coins obtained in a decentralized manner.  How decentralized and open source.. is another discussion but hopefully it exceeds expectations.  Thing is, there is a large market for Bitcoin privacy and fungibility.  I would imagine many would pay big prices to have some privacy over here, so who gets to offer the perfect solution will earn money big time.

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Regards,
PrivacyG