Looks like Mac OS Big Sur broke this completely, even the JAR. At this point I'm not sure it's worth trying to support it. Apple doesn't really care about small developers.
Viewing post in New public build, v0.3.12.0! comments
Personally I don't use the macOS bundle, I installed a JDK (AdoptOpenJDK) and download the .jar file and run that instead. Works much better as the macOS build is always having problems.
However it seems like the latest release (0.3.12) is broken for all platforms right now (crashes on startup), doesn't seem to matter which version you use.