If you really need to get your samples out of BFD - check out Xtractpler (https://www.xtractpler.com/)
It doesn’t convert the samples. It plays them all, routes the sound to a recorder and re-records them as .wav. You can set which midi notes it should play and which (and how many) velocities it should play and record for each note. It has a bunch of keymap templates so you may not need to manually set up the notes. It is a bit technical but works.
I’m not affiliated in any way with xtractpler, (If I was I would have chosen a different name for it!) but I have found it useful when I needed to pull proprietary sound formats from my VSTs and load them into my drum module.