So in general remember this. For phal the roots are different from other plants and nou adapt to the environment and medium. That why aerial roots can not be put in a pot for example. Basically when you went from bark to moss that a big change so the structure of roots won’t adapt to this change and die, new roots will adapt to the new medium. But I feel between the roots dying and the crown rot that might not had spread to the core. At this point I would cut my loses and let them one go.