hell even DRAGON BALL, one IP alone, has super different styles
it's subtle but everything from the hair, to the cheeks, to the facial features are slightly different and have different styles (these are like 3 of the most well-known art styles for dragon ball)
forgive me for i'm not an artist... but i don't think it takes an artist to see that anime is very diverse in art style too? or are you going to tell me these all look the same (or even similar)