The Apple TV example looks a bit disingenuous, the huge black space normally holds an image promoting one of the shows. That’s why it has so much space. I don’t know why in his situation the header is empty but that has nothing to do with layout on small screens. You could complain the promotional image is too large but it’s really obvious you can scroll down to reveal the rest of the content and I don’t think anyone is contesting the conclusion that yes, a small screen fits less content without scrolling.

The Apple Shortcuts (which by the way is an acquired app that was not originally designed by Apple) problem indeed is a bug in the way the sheet works, probably because of the custom keyboard like icon picker at the bottom, which is really poorly designed anyway. If you have an iOS device, here’s a riddle:

If your device has a larger screen than the one in the article and you try to recreate it (on ‘My shortcuts’ navigate back, then tap the add folder button), you can choose from a larger set of icons. Someone with an even larger device than yours would see a palette with even more icons. But on your device you can get to these icons as well, try to find out how!