Valuable feedback, thank you.

Regarding the prompt for language and theme: I actually received similar feedback via email. Instead of adding a popup, I decided to make it seamless—I just updated(locally) the app to automatically detect your OS settings for the Theme (Light/Dark) and Time Format (12h/24h) and apply them by default. This way it should "just work" for most users without needing an extra click.

That's even better. Do remember that the OS language isn't the preferred language. From HN you should really link to an /en version.

My formula is to ask what it is the user should be doing on the page. Not even what they think they should be doing, what they actually should be doing. Why are they there?

Then you give the visitor only what they need step by step. People are great at screwing things up. Rob them from all opportunities.

In my day job I actually use quite a few train apps. If I have several train or trip numbers in my head everything that is not a search box is wildly annoying.

Wait.. let me slap something together....

https://img.go-here.nl/train-app.png

There, except from a settings icon that is how I would make it.

Enjoy