So far I'm happy with the choice. The ecosystem is mature, the build tools (maven/gradle) are solid to build this more complicated project, JavaFX works well enough to realize cross-platform applications, and the performance with modern JIT compilation from GraalVM is good. Currently I'm not missing something important from the tech stack.

Next week, when JDK 24 is released for the general availability, I plan to immediately switch to that as there will be additional performance gains with Project Leyden's AOT compilation and Project Liliput's memory improvements. So I'm positive for the future.

Go and Rust are more suited than Java for building graphical user interfaces that run cross-platform? That would be news to me.

Sure it can be done, but it's not exactly like there are well-established solutions for this.

Can you name the top three reasons why Go or Rust would be better for this?

Neither Go nor Rust have a GUI toolkit anywhere close to the capabilities of JavaFX, so in practice such an app would largely be written in JavaScript. If you want to use one language for your desktop app, be portable, and avoid the complexities that come with web development, Java is the best possible choice today (arguably the only choice other than maybe Qt).