I would say that your best bet would be to learn React Native. It’s an excellent option for mobile apps and you can reuse what you learn for a lot of other things as well. It’s super popular so you should find no shortage of resources if you get stuck.
Another option is Flutter. I personally don’t like it too much unless I also intend to target desktop (and even then I’d probably use something else) but it’s fairly popular as well so you should be able to find plenty of learning resources.
Ahh Kongregate. Haven’t heard that name in a long time. I’m surprised they’re still around.
You’re welcome! Have fun!