I made https://github.com/AlvarBer/Persimmon, I would say Kivy is pretty capable.

My biggest caveat is the kV lang, when you get to dynamic components you almost always have to either give up and do the ugly manual bindings by hand, or hardcode a lot of values.

A friend made a game for learning Morse Code, called Morsey. I'll see if he wants to give some comments on the experience.

Heres the google play link: https://play.google.com/store/apps/details?id=org.morsey

In the same vein, I'm curious about the workflow and tooling here. Being used to Visual Studio+XAML kind of WYSIWYG editing, is there anything similar in Kivy? Or do you write code, run app, close app, repeat?

I put together a photo booth using Kivy and use it occasionally at weddings. I was able to get the inital project going in a weekend, but I've been maintaining it for a few years. I'd use Kivy for another project, and reccomend it. That's not to say it's perfect, but overall it is enjoyable to use.

I created a game which was a clone of Winterbells. It was when I was learning to code.

This was many years ago, however I recall it being quite easy and enjoyable but very limited.