Official comment
I'm not going to get technical because I don't want this to be taken as any kind of official answer, whether here or quoted / screenshot and shared elsewhere... but Apple made changes in Big Sur that broke some audio and MIDI things for a lot of manufacturers, which is why we're not the only ones who haven't released an update. We know there is a fix coming from their end, and we've tested stuff on our end to know it will address the problem, we just don't have a release date.
Thanks for the patience.