I feel like people often forget that Ben isn't dumb. He's just surrounded by super-geniuses.
The guy is a literal astronaut. You gotta be pretty dang smart for that. But he's surrounded with the likes of Sue and Reed, who are both extremely intelligent. He also has frequent run ins with Spider-Man, Iron Man, Black Panther, etc. who are all definitively smarter than him, but my guy Benji is still *really* smart. He's the smart man's "dumb man".