
A lot of anime/manga are set in high school because in Japan that’s pretty much the only age range where you will be truly free and able to have these sorts of adventures. Corporate world in Japan is soul-sucking lol. I agree though that more popular shows tend to have meh writing most of the time!
Demon slayer is agreed by many, it’s not terrible writing at all but the animation does carry it to where it is. Take the fate series for example: made by same studio with spectacular animation and sounds but the stories are confusing with very little leeway on new anime watches for the story across its series