I would reinstall Finale -- it's likely That Migration Assistant hasn't brought over everything you need. 

If you're sure that all the other components have been brought over -- Document Styles, VST/AU plug-ins, etc, then there is a font installer on this very site:

https://makemusic.zendesk.com/hc/en-us/articles/1500013053461-MakeMusic-Fonts-and-Licensing-Information

Thanks for suggesting this, but I'm not going to run Finale on the new computer. Once I upgrade it to Sequoia Finale cease to run, I think.

Firstly, Finale works fine on Sequoia. MakeMusic just won't help you if there is a problem.

Oh, so the fonts issue is on the old Mac? Well, the advice still stands. Reinstall the fonts.

Really? Great! So I just go to the MM siter and download it into the new computer?

It won't hurt to try! It works for me, and several others have reported no problems.

OK. The new one is still on Sonoma, but you've given me faith that once I update I'll still be able to use it. I just downloaded it into the new one, but I'm going to make sure all my F files have been converted to XML before I try. (Paranoid? Oh Yeah!)

By gibberish, I think you are looking at SMuFL fonts - thus the SMuFL version of Maestro called Finale Maestro, not to be confused with Maestro - the legacy (original) version. I found this rather bothersome opening previous scores in Finale 27 and in the end made my default option original recipe Maestro. 

https://www.scoringnotes.com/reviews/finale-version-27-1-smufl-burrows-deeper/

Finale 27.4.1 runs fine over the current macOS Sequoia. MakeMusic won't support it — oh well. No one has run into a Sequoia specific Finale problem yet that I have seen—it's always something else.

The first builds of Sequoia messed up Permissions on some users' Macs big time, mine included. Perhaps this is what scared off MM Support. Trying to install a test volume, I accidentally upgraded my System drive. Interestingly, Finale was one of the few apps that still worked but Mail, Music, Word, Adobe and most of my other bread and butter apps did not. I worked with Apple over a month getting it resolved. Again, incorrect Permissions was the problem every time and I figured it out, not they. Although I did not care for the inconvenience of Sequoia Hell during that period, Apple learned a lot. I was paid for my contributions and I sure do like that. Anyway, it's safe to jump into the water now.