Then I remembered some years ago, in this similar situation, I decided to learn (invest time on) JavaFX when Qt, gtk, Xamarin and web tech were the alternatives.
Well, yesterday I googled, after all these years, if JavaFX apps can be run on Android devices (spoiler: no, or not in a usable way)
Now, in hindsight, I know that I put my egg on the wrong basket by focusing on Java and JavaFX. I was deluded on their write once run everywhere promise. I feel betrayed by Oracle due to their detaching of JavaFX from default JDK.
I think if I chose to focus on a web tech frontend framework (or even Qt) I'd been better off.
Thanks for coming to my Ted Talk.