I have had similar experiences to OP. All of these apps (mostly maths learning, but also the bus one) were coded using a mix of copilot and Gemini CLI: https://rupertlinacre.com/

I'm probably capable of building all of them by hand, but with a 6yo I'd have never had the time. He loves the games, his mental arithmetic has come on amazingly now he does it 'for fun'.

All code is here: https://github.com/rupertlinacre

Much of this built out of a frustration that most maths resources online are trying to sell you something, full of ads, or poor quality. Just a simple zoomable numberline is hard to find