Spoiler for like, any book existing.
I think mine has to be the villain in Mirror Man. Idk, he wasn’t intimidating, he wasn’t interesting. He was meh.
Also the villains from The Chain. Dear God they weren’t sympathetic in the slightest. The book tries to act like they were atleast pitiful but FROM THEIR INCEPTION, they were just evil assholes who enjoyed causing pain. The book itself wasn’t all that great anyways.
For Evil Stupid I nominate Thanos.
Powerful, willing to kill huge amounts of things, 0 understanding that it’s simply a bilp on the timescale of living beings. The black/bubonic plague killed about 1/3 of Europe. Slowed things down for maybe 100 years with a completely inefficient economy.
In the comics, he’s just trying to get Lady Death to fall in love with him. (That’s why there’s that line about courting death at the end of Avengers.) He killed half the universe as a present to her. She reminded unimpressed.
In the movies, though, you are correct. He’s the embodiment of Malthusian stupidity. No matter how many times it’s disproved by history, people keep falling for it.