When Marvel Studios decided that Kang wasn't clicking as the Multiverse Saga's big bad (Jonathan Majors' legal issues also factored into that, of course), Kevin Feige decided to pivot to Doctor Doom.
At last year's San Diego Comic-Con, we learned that Robert Downey Jr. will play the villain in Avengers: Doomsday and Avengers: Secret Wars. While that's an exciting prospect, many fans feel Doom would be better served having a history with the Fantastic Four. After all, despite frequently clashing with The Avengers, he's primarily one of that team's villains, and his connection with Reed Richards dates back to their college years.
The Fantastic Four: First Steps is now playing in theaters internationally, and the movie is arguably Marvel Studios' best opportunity to establish a connection between the MCU's First Family and Doom before Avengers: Doomsday's release next December.
While Doom does appear in the reboot's mid-credits scene (you can learn more about that here), there's no mention of this iteration of the team having previously crossed paths with Victor.
Latveria does, however, exist on Earth-828 as there are a couple of scenes where we see the country's flag in the U.N. (the seat next to it is empty, suggesting Doom's nation has declined to send a representative, even with the world facing annihilation).
The opening montage makes no mention of Doom, and neither does the team's cartoon intro that features villains like Dragon Man, Puppet Master, and Diablo. Downey's Victor might have faced the Fantastic Four on his Earth, but it would be strange for this version of the team to first encounter Doom when he seemingly kidnaps their child.
Sue's reaction to Doom being in the Baxter Building isn't shown, and it's down to Avengers: Doomsday to expand on the stinger and whether Victor's quest to "save" the Multiverse begins on Earth-828 or whether this is just his first stop.
Marvel Studios looks to be hedging its bets, and The Fantastic Four: First Steps makes it so that Doom could be from Earth-828 if Avengers: Doomsday decides to head in that direction. Alternatively, it might be that there's only one Power Cosmic-imbued Franklin Richards in the Multiverse, and it's that which drew Doom to Earth-828.
Still, Latveria has never been mentioned on the Sacred Timeline (Earth-616), so the fact that the fictional country exists in the Fantastic Four's reality has to meet something. We'd bet on Doom being from Earth-828, but let's wait and see.
In our review of the movie, we concluded, "The Fantastic Four is an exceptional introduction to the MCU’s First Family, and thanks to a Jack Kirby-infused feel that’s unlike anything we’ve seen before, it proves to be a quintessential superhero movie with Marvel Studios at its brilliant best."
The Fantastic Four: First Steps is now playing in theaters.