Thanos was born with power and everything he wanted was given to him
Umm... yeah, you don't seem to have any actual clue what you're talking about, because the character you're describing isn't Thanos of Titan. It may be Alexander the Great, who inherited a powerful army from Philip of Macedon, but Thanos?
Thanos was born with powers, yes, but he augmented his natural powers through technology and sorcery far above what he was born with, making himself the most powerful Titan.
"Everything he wanted was given to him". What in the world are you talking about? Nobody ever gave Thanos anything (With the ONE exception that Death augmented his powers upon his resurrection, but that was the one and only time. Every other power boost he's had he got on his own). He was exiled from Titan when he was 18 for vivisecting his mother among other crimes, and spent a century out in the universe on his own gathering an army, a fleet of ships, as well as making himself more personally powerful. Nobody gave him any of that.
Doctor Doom came from nowhere and built his power and empire, he built almost every devices he has, Thanos didn't, it was given to him or he stole it, how does having more toys makes Thanos smarter?
Once again, it's clear you don't have a clue what you're talking about. At the very least look up his entry on the Marvel Comics Database. Reading a wikipedia entry isn't that hard. From the Marvel Wiki...
Superhuman Intellect: Possibly Thanos' most dangerous ability is his mind. Thanos' intellect is dedicated to enhancing his own powers and to the annihilation of all life.
Thanos is a genius in virtually all known fields of advanced science and has created technology far exceeding contemporary Earth science. His intellect surpasses Earth's greatest minds, Reed Richards and Doctor Doom.
That's straight from Marvel itself. And that's amply supported by the comics. If we were to believe what you said, that Thanos stole all his technology, then 90% of his stories wouldn't make sense, because most of the time is spent with Thanos puzzling problems out. Most of the technology he uses he made himself, which is evidenced by the fact that
nobody else has it. Just look at Annihilation. The good guys were winning up until Thanos joined forces with Annihilus and gave him his technology, and suddenly that shifted the tide in favor of the Annihilation Wave and made victory over them hopeless. So who'd he steal that technology from if he's the only one who knows about it?
Likewise, he was the only one who figured out how the Power Cosmic works, and was the one that Annihilus went to to turn Galactus into a weapon. And look at Infinity War. He gave up his old life to live as a farmer on a backwater world but, what does he do? He builds a massive superlab under his house which allows him to detect the energy output from the machines the Magus is using. This is a guy who even created clones of Galactus and other super-powered beings... and he did it just for the Hell of it just to pass the time, and not as part of some scheme.
That's like saying Queen Elizabeth is smarter than Albert Einstein was.
I have no idea what this metaphor is supposed to mean, but if Queen Elizabeth created legions of clones, developed teleportation technology which millennia old galactic superpowers don't possess, and can build a superlab which can detect energy signatures from several universes away from scratch and by hand, then yeah, Queen Elizabeth WOULD be smarter than Albert Einstein, wouldn't she?
Like Harlekin said, Thanos may be more vilainous but Doctor Doom is the better character
Thanks for adding another vote to Thanos, then.