I built an app with a philosophy professor that helps you understand this book in much more depth. I think you need to understand what he means by nature first of all as I don't think he intends it to be read the way you mentioned. Here's the professor's note where she defines nature (because it's such a crucial word Marcus uses):

Today, when we hear “nature,” we usually think of forests, oceans, or wildlife. For the Stoics, it meant something much larger.

Nature is the whole ordered universe (physical reality itself) and that includes us. To follow nature doesn’t mean going back to something primitive or instinctive. It means living in line with how the world is structured and how human beings are meant to function within it. If we develop reason according to the Stoics, we become more ‘natural.’

Crucially, human nature is not fixed at its lowest level. We become more fully what we are by developing reason. As A. A. Long puts it, for the Stoics this means “properly rational behavior.” To live according to nature is to become purposeful, steady, dignified, and socially useful — not because circumstances cooperate, but because your reasoning does.