I didn't like how the plan wasn't Victor's. Felt like it could have been anyone who MM chose to execute this plan.
MM didn't expose it in this issue but bear in mind he offered this to Doom
because he was working with him on understanding the incursions.
It seemed pretty natural to me as such a plan would require a very particular kind of anti-hero: someone who could spend 25 years killing Molecule Men and destroying countless universes, all for the greater good, someone who could form a cult and lead it to further these goals and someone who could ultimately stand up to the Beyonders. All that without relishing nor flinching at the horror of it all.
Honestly, besides Doom, the only other person who'd fit the bill I can think of is Immortus/Kang. Except Doom is the one who came across Mapmakers and decided to study whatever was going on. Plus, Doom is a scientist and a Sorcerer, which is necessary to enact the plan (leading a cult and understanding the cosmic scale).
But yeah, Doom worked inside a framework offered by MM but in the end, he's responsible for the execution of the plan.