Have you found a way to implement this proportioning model in a way that natively scales to multiple phone sizes and screen ratios?

For example, if that design is for an iPhone 6 or 7 the proportions of elements (like the large photo at the top) change with auto layout when scaled down to an iPhone 5 or up to a 6 plus / 7 plus. And on Android there are also some devices that aren’t a 9:16 aspect ratio.