FlashBuddy VS Useful-Things

I've done something similar with maven for a recent project, you can check my pom.xml here.

Creating fat-jar's for maven/gradle projects each release using automated CI (Like GitHub Actions, or Jenkins)

You can refer to my example demonstrating the fix if you want a visual here: https://github.com/Col-E/Useful-Things/tree/master/tutorials/javafx/maven-setup/src/main/java/org/example

On the other side, I think you did a really good job illustrating how DI works with this document.

No, just use a normal Java template for Maven/Gradle and add JavaFX as a dependency. I have examples here: https://github.com/Col-E/Useful-Things/tree/master/tutorials/javafx

JavaFX FatJar with Maven

Using Maven, declare JavaFX as a dependency

If the steps are confusing, I have a maven empty demo project here: https://github.com/Col-E/Useful-Things/tree/master/tutorials/javafx/maven-setup

You can make a sorta kinda "Multi-platform" JavaFX jar, but only for one architecture per OS. Their dll/so/dylib path names all conflict which is infuriating.

I typically roll with a standard fatJar plugin. I made a short guide for somebody before. Is that the direction you were looking for?

Check the reddit links in this post.