Unfortunately, since I used RPG Maker to make Jimmy, I don't have the know-how nor resources to make that kind of update. It does seem like there might be some workarounds as per this article:
https://www.pcmag.com/how-to/how-to-run-32-bit-apps-in-macos-catalina
...but that seems like it's going to be complex. I'd love to hear if anyone is successful in getting this to run on Catalina.