Its not good design, that's the key thing. It works cross platform but makes for poor UX.
One solution is to have the UX/UI transition to bottom half of the screen when Win10 detects its running on 6" or smaller screen. Think of this way a tablet you will most definitely use two handed, so controls can exist at the top for the most part. Anything smaller like a phone should be operational single handed all the time, no matter what.
Think of a one armed person, on a tablet or pc/laptop whatever they have other modes of input, pen, mouse, touchpad or even touch, etc that can still give you ease of use single handed (those devices are rarely used while walking or doing casual things if anything once you set it to the screen you want say for reading you would pick it up and walk and read and sit down somewhere else or whatever. A phone type device on the other hand should be used single handedly, reading info and writing a note with a pen in the other hand while still navigating the phone, or the one armed person where they walk and need to use the phone without fumbling and possibly dropping a larger device, if your wondering why they would get a large device what if they have poor vision too?