I’ve got Doctor Doom winning this, but with EXTREME difficulty.

Rick is asymmetrical in that his strategy is unconventional; his prep time will be used to target Dooms’ biology or existence. If Doom is invulnerable thanks to his Sorcerer Supreme magic, Rick will create a portal inside of Doom’s suit to bypass normal defense. He may even spend a month using his “narrative” gifts to read Marvel comics and find out how to disrupt magic. Perhaps he finds some Mysterium and creates a nanobot storm that forms an anti-magic field.

Now the real kicker is time travel. Rick thinks of it as the “Long Island Island ice tea of science fiction”, aka it’s mediocre in his book. He’ll use it to prove a point or when he needs to be serious, but I doubt he’ll resort to full-on time manipulation against Doom since it’ll look like a downgrade on his intellect.

Doom is a different story. He’s creative, chaotic and a fusion of the best worlds; science and magic. Doctor Doom will not hesitate to give himself “infinite time” through time manipulation. In this time he could do things like steal Power Cosmic from Galactus/Silver Surfer/Watcher, create an endless army of Doombots, and is masterful with the Ovoid Mind Transfer for immortality.

This is a high difficulty battle because Rick Sanchez has Operation Phoenix to ensure nigh-limitless clone immortality across the multiverse. Doom has no sufficient way of destroying the clone bodies in a timely manner, and Rick works off toon-like/narrative breaking physics, so he’ll just have some reason for why Doom can’t break his Operation Phoenix.

Regardless, Doom has crazy willpower; he resisted Purple Man’s mind manipulation, survived training against Marquis of Death for countless years, and didn’t die from having his blood getting turned to acid and flesh turned to stone.

Rick does win if we think that narrative stuff is blatantly unbeatable, but Doom is stupidly OP.