Unfortunately Audible seems to be applying a new DRM lock to prevent downloads of the Dolby Atmos version so unless this is cracked some day, there won’t be any more downloading of those.
Well, determined people can always go back to the analog method: reencoding the audio output.
Not as fast or as perfect as pure digital decryption, but with the ridiculous bitrate they use, it would be pretty good.
Personally, I don't listen to audiobooks for the effects. Most books I set the equalizer to mono ... But to each his own.