Uncanny valley works when you see something that looks like a human but isn’t quite is and you start panicking as a result, but it doesn’t happen with cartoon/anime characters, They’re clearly close enough to humans that people are attracted to them but the affect isn’t the same
Cartoon characters distinctly aren’t close enough to humans to trigger the uncanny Valley. You look at them and instantly realize they aren’t real humans (you don’t second guess yourself or feel some thing is off).
Cartoons do tend to possess exaggerated attractive characteristics such as big eyes and bodily figures. In addition, a cartoon character is still “played” by a real person and has personification like personality, goals, foibles, etc.
People can be attracted to literary characters that exist solely in someone’s imagination using text as inspiration and that same mental gymnastics can transform a cartoon character into someone more real in the minds eye (kind of a reverse of how caricatures are easily recognizable for the original subject).
Uncanny valley is when a picture tries to fool us into believing it is a real human. What spooks us is the human that isn’t human.
Big anime tiddies
Anime characters are in the other side of uncanny valley. Cartoonish enough that they don’t fall into that pit.