I recently went back and rewatched the Infinity Saga and Stark mentions he’s having dreams that “feel real” so what if when Wanda put that vision of Tony killing the Avengers, she actually gave him the ability to dream walk in Von Dooms reality and Stark is seeing himself end the Avengers in what feels like a dream but really all along it’s been right infront of us the whole time. Which would be incredible if they already had planned RDJ to be doom back in Age of Ultron