Theory regarding Doom and Tony that connects to Endgame
As you have seen Endgame, Tony came back with the shield during underground scene and something was a miss with that scene. Like that Tony knows something that we don't as he also said, "You mess with Time, Time tends to mess back".
So what if that Tony of ours already went through the events of Doomsday and Secret wars and found out he's not a stark but a Doom variant. In those two movies, he'll be confused and will try to find his place and in the end he will.
That way it will not matter to him whether he's not a Stark or a Doom variant cuz he was and always is Iron Man. And that way he'll finally accept himself and say the line tha will connect everything to Endgame, "And I am Iron Man."
So what if that Tony of ours already went through the events of Doomsday and Secret wars and found out he's not a stark but a Doom variant. In those two movies, he'll be confused and will try to find his place and in the end he will.
That way it will not matter to him whether he's not a Stark or a Doom variant cuz he was and always is Iron Man. And that way he'll finally accept himself and say the line tha will connect everything to Endgame, "And I am Iron Man."
Commentaires
The two characters are similar archetypes and that’s all it could be. The audience fills in the gaps of Doom’s story and motivation by comparing him to Tony which they are already familiar with.
Maybe they’ll have *some* explanation as to why they look similar, like, for the few people or kids actually asking that question. But they could also just have RDJ look different enough from Stark where they don’t need to explain it at all.
Doom is scarred behind the mask he wears 99% of the time.
I do like the idea that maybe it's not Doom that is a Tony Stark variant, as the Russo brothers confirmed, but it was Tony Stark that was a Victor Von Doom variant this whole time. People might not like that level of "retcon" though, even though it really doesn't change anything about Tony's past, outside of him maybe being actually adopted from Latveria.
We know in Endgame Tony seems puzzled by Howard Stark saying his wife's pregnant, like the math doesn't add up. Maybe he was adopted this whole time. Not the worst retcon IMO, and it goes to show Howard Stark was an amazing innovator and father that could set even Doom on the right track to become the hero that would save the world.
Then there's the theory that Steve Rogers tampering with time results in the events of Doomsday. Maybe there's a butterfly affect that results in Tony not being adopted, and that is the Victor Von Doom we will see in Doomsday, who will presumably go on to form Battleworld as God Emperor Doom in Secret Wars.
Technically, Steve Rogers had a spare Pim Particle he didn't use because he never made the trip back, he just aged to the present day. We know he went back and did something he always wanted to do, live a life with Peggy, but what if he went back and corrected something else he regretted with the spare Pim Particle?
He goes back and saves Bucky from ever being brainwashed by Hydra. This has a crazy butterfly effect on the entire political landscape of that timeline as there is no winter soldier. Maybe Sekovia winds up becoming Latveria, RDJs Von Doom never becomes an orphan, his mother is taken by Mephisto, and the rest is history.