Doom isn't Tony or Victor

He is a Howard variant. Gotta credit Colton Ogburn for the idea that this all has something to do with Tony meeting his dad in the Time Heist. When Howard says that his wife is due, Tony seems taken back at the date.

Then there is the Tapestry that Doom is looking at in the trailer. Of the Woman and her Son. I think it Maria and Tony.

Then this part is a little more crackpot, but if you read The Ultimates, Tony and Howard are related to a certain character who was supposed to be the big bad instead of Doom in this movie.

Just my hunch. Doesn't explain the accent. Probably just a Victor Variant