Privacy tools like Whirlpool from Samourai Wallet never take custody of users bitcoin. Users are not sending bitcoin to an entity and receiving it back. Whirlpool is free open source software that coordinates non custodial coin joins.

Whirlpool Samourai Wallet allows users to legally break the on chain deterministic links by collaborating with one another in a peer to peer fashion.

https://blog.samourai.is/learn/

https://primal.net/e/note15wknn4wkwj060camt5re7ereazpwsdqzm9tcr8zclhxqdj86pg5spfsevl