For the people having apprehension around Java’s performance, let me tell you that my 12-inch MacBook with a mobile CPU managed to run IntelliJ IDEA just fine (a heavy Java-based IDE) but significantly struggles with Microsoft Teams (Electron-based chat client).
Yeah. Java's default performance isn't bad, and the floor is quite good (lots of space to optimize if needed). Just avoid bloating it up with enterprise framework when you don't need them.
JavaFX doesn't seem as snappy as native OS GUI frameworks, but I've found it very nice to develop for. It comes with reactive model out of the box, and there are some extra libraries that take it up to 11.
