It's truly unfortunate that none of the issues reported in this thread have been detected and corrected preferably during the long period the Beta version of Big Sur was made available or alternatively immediately after its release, as it happened with pretty much all the other programs I own for Mac.
This issue We have been testing Band-in-a-Box on Big Sur and Apple ARM hardware for some time now, basically ever since the first Beta version was available to us, and we had nearly zero problems with it. None of the issues with crashes or pink colours popped up for us at all. Unfortunately, the public release version of Big Sur is not the same as the beta, meaning that we were unable to test on the public version before it was released.
There will be announcements and a build update when these compatibility issues are resolved, likely sometime in December.