No, it's not a fact, it's an opinion. There's not an accomplishment in Doom's resume that shows he's smarter than High Evolutionary. He's more battle tested than High Evolutionary, granted, but smarter, with better tech and inventions, and better feats of intellect than High Evolutionary?
No.
Doom is NOT smarter than High Evolutionary, and Doom does not posess more personal power than High Evolutionary. Also, to say that Doom would unequivocally beat High Evolutionary if both sides had equal prep is debatable in of itself, particularly given what High Evolutionary has already done and is capable of.
So yes, it's reputation and "Doom is Doom, so Doom wins", not fact.
And while High Evolutionary didn't finish second in the Sorcerer Supreme competition and hasn't sold the soul of his loved ones for borrowed magical power, that's not a feat of Doom's intelligence, that just shows the depths to which Doom will go to in order to gain power. Doom's magic knowledge and affinity isn't just a result of his intellect, it's also passed down through his heritage (from his Mother). High Evolutionary's arcane knowledge is good enough to amplify villains in his employ, negate magic attacks, and arm his New Men to battle demons and Chthon. I'm not saying High Evolutionary is a powerful sorcerer, I'm saying he knows enough about magic to provide adequate defenses and countermeausures against it so that an opponent wielding it doesn't have an advantage.
Doom is not a better inventor or engineer. There is not a field of science Doom is more proficient in than High Evolutionary. You can't say the opposite.
High Evolutionary is smarter than Dr. Doom.