Well, he never says he’s evil but is certainly seen as a villian: Dr. Victor van Doom. He’s actually glimpsed all possible timelines of humanity and only the one where he reigns is not ending in destruction. https://qph.cf2.quoracdn.net/main-qimg-4d9668819558c73a8fda43cd4bc0ef0a-lq He is also loved by the people of the country he does rule. And when he had indeed managed to rule the world, it was a time of peace. I mean, mind control peace (he amplified the power of Kilgrave the Purple Man) but still.
If you’re asking yourself why Kilgrave didn’t simply control him, Doom is one of the few people with so much natural willpower that Kilgrave’s powers don’t work on him: https://i.pinimg.com/originals/d5/e8/c8/d5e8c8ee71120993b8616128b08a6a22.jpg
Doom in the comics is more like movie Thanos than comic Thanos. Comic Thanos is legitimately mad and killed half the universe just to impress Mistress Death (she was not impressed).
He’s basically Stark, Strange and Black Panther rolled into one, with the arrogance of Strange and Stark dialed to eleven.
He’s completely capable of doing very evil shit to reach his goals but also has moral principles. He has tried to kill the Fantastic Four countless times and is still the godfather of the daughter of Reed and Sue. Her first word was “Doom”.