I just wanted to post this idea that might be possible to solve Windows App limitations.
Wouldn't it be possible to join the Windows App with a .exe service that can be downloaded through the Windows App itself to enable extra features that Windows App cannot support by its own?
Once you want to enable the extra features such as auto copying in Windows App it will ask for installation for another .exe service from join website? that will allow you to bypass all of the Windows Universal application limitations.
Once the extra .exe is installed it will take care of enabling many missing features that are too much to mention (auto copy, and much more).