It seems like the echo cancellation that is known from iOS devices is also available on macOS, as indicated by this
announcement from the Chrome team. It seems like they had some good experience with it, so we'd like to explore it as well. Would it be possible for you to check if support for this could be added to BASS for macOS similar to the iOS version?
I've found
this post on the Apple developer forums where someone's trying to use it but seems to have issues with it, but maybe that post can be used as a starting point to explore the feature. As it seems to require a change in the AudioUnit usage, I guess it's not something we cannot bolt onto our application without a BASS update.