If your Fantastic Four movie came along, wouldn’t it make more sense for Doom to be from Sokovia?

I don’t know. Sokovia isn’t the best thought-out part of the MCU to begin with – there’s a nebulous civil war, Stark is selling arms, HYDRA infiltrates, yatta yatta. 

That doesn’t seem to be a great fit for Latveria, where the emphasis is on totalitarian order and control, rather than civil war and instability.