Let me put this a different way.
As a regular streaming television show watcher, I want to have a centralized repository of the top 20ish shows that I regularly view so that I can quickly start watching the next episode of one of them without having to go into any particular streaming service to find it or even having to remember which streaming service hosts it.
Given that the user is interacting with the main Roku menu, when they select My Favorites, then display a tiled list of streaming TV shows that they have favorited.
Given that the user has selected one of their favorites, when they press OK, then open the appropriate streaming service and start playing the next unwatched episode.