Are mixing/tumbling services really safe anymore? Could this be accomplished as a fee-based option in the process of trading on bisq?
afaik, there is no such functionality being developed in Bisq atm.
Btw, concerning wasabi mixing service, there are some recent news which are not so reassuring:
I like the idea of having mixing as an additional way to get funding for the bisq development, but i think this is a low priority development goal.
With https://github.com/sipa/bips/blob/bip-schnorr/bip-taproot.mediawiki there are higher incentives eventually to reduce fees by combining multiple transactions into one.