The Design Team is far bigger than it was at the start of the edition.
Using Beyond is not either. Beyond is pretty much a pure positive for expanding the game. It’s not taking anything away from the print books.
The gods don’t seem to know or be able to reach Vecna.
Like the player characters are explicitly only able to reach him cause of a link they share with him.
It doesn’t get into Eberron’s cosmology as it’s just a short visit, Lord of Blades doesn’t show up himself, but his agents are the primary antagonists of the chapter.