As I'm becoming a senior developer in terms of age, I've transitioned from one language to another. One of my main interests has always been clean, easy-to-understand UIs (User Interface). That journey started for me with Director (to create multimedia CD-ROMs), Flash website animation, and Flex Rich Internet Applications (= "Flash on steroids"). When I started developing with Java over 10 years ago, we had some projects with the early versions of Vaadin and JavaFX. As I went on with serverside applications, I only continued with JavaFX for some personal and side projects and loved the way you can create a UI both with XML (FXML actually) and code, exactly the same approach I loved with Flex. Since then, my love for Java and JavaFX only grew and it's still my major programming environment.
But JavaFX has one missing piece: running it in the browser... Yes, JPRO can do this, but it needs a license and a dedicated server. And yes, there are some projects ongoing to bring JavaFX fully to the browser, but they are ongoing and not mature yet... Let's look at another approach: Vaadin Flow and run it on a Raspberry Pi to control a LED and show the state of a button.