I had a thought... do you guys remember Fant4stic? the very bad attempt at Fantastic Four reboot from 2014? A big plot point in that movie was how Victor Von Doom, who disappeared when the team first went to Planet Zero, suddenly is rediscovered, fully suited and powered and almost immediately believes that to protect his new realm, he must destroy Earth (for reasons nobody has any clue why).
Anyway, I thought about it, and came up with a bit of a narrative fix...what if Doom in that version was an alien sort of? Like, what if Victor Von Doom managed to crack interdimensional travel years ago, but disappeared and the decades in that realm turned him into Doom. And instead of saying he wants to "protect" his world, he wants to conquer our world and make it part of his new home.
A bit tropey, maybe...but way more sensical than the version we got.