Replying to my own post, I think I've found a solution, thanks to this post:
The author complains that it's working for him only if he connects his iPad directly.
Doh. That's the one thing I had not tried 🤷
So with that said, I've just expanded the xcode project from the link I've pasted before, then added my daughter's code to
main.py. I've chosen my iPad as destination to run, and of course had to tell XCode to use my profile.
Once that's done, I can easily deploy on the iPad.
From there, it should not be a fundamental problem to create an app for the appstore out of it. To be explored next...