You should open a support ticket on this. Be aware that Finale has not yet fully endorsed use on Big Sur.

The complaints I've read seem to revolve around Garritan.

So many of my apps and plugins are not yet compatible with OS 11 that I've not loaded it onto a test machine yet.

Hi Jan-Erik, thanks for posting.

We do now list Finale v26.3 as compatible with macOS 11 Big Sur and there are not any known issues with the Garritan instruments that are installed with Finale. If you are seeing the an Audio Engine Error message, most likely the problem is with the audio hardware connection on the machine and not Garritan or ARIA Player related. I have opened a support ticket for you, so feel free to respond to that when you can and we can take a closer look into this to locate the problem. 

David, can we expect an official announcement of this? The blog still has the older recommendations.

Mike, the blog post and our knowledge base articles have recently been updated to reflect this. 

https://makemusic.zendesk.com/hc/en-us/articles/360054240594-Finale-and-macOS-11-Big-Sur-and-Apple-Silicon

https://www.finalemusic.com/blog/finale-v26-compatibility-with-macos-big-sur/