As I said, what’s shown in your video doesn’t work here. Flash is already turned on in Edge, and the Adobe Flash page basically says “Flash is included with Edge but it has been disabled on your machine.” Unfortunately, none of their suggestions for enabling it actually work.
Guess Edge needs a registry tweak like the one for Chrome, above.
Update: tried editing Group Policy and Registry with various suggestions from the web, but nothing works so far. . . 