hair too, most people most of the time will do just fine with a simple bar of soap in the shower, all shampoo does is detonate a nuclear bomb on your scalp so you then have to put oil back with conditioner, it’s the textbook definition of making you dependent on a product.
you only need shampoo if you have some specific scalp condition or you decided to rub shit on your head, otherwise soap is absolutely fine and frankly you’ll probably do fine with just water and rubbing yourself down thoroughly.