The 4K quality is tied to some pretty specific hardware and drivers as far as I remember. And 1080p is also different in my experience in the Windows 10 App and in Edge. I was able to get 1080p for some content in Edge, but not everything. The only way to consistently get 1080p quality was to use the rather crappy App. The search and filter features were worse than the website in my experience, and I ran into quite a few bugs when I used it.
