Hilariously, my littermate cats are opposites, one doesn’t notice it at all, while his brother absolutely goes wild for the stuff. So cat 1 just sits there all judgmental watching cat 2 roll around

There are two closely related species: Catnip (Nepeta cataria) and Catmint (N. racemosa). If your cat isn't attracted to one, there's a good chance they will be triggered by the other.