https://psyche.co/ideas/when-your-authenticity-is-an-act-somethings-gone-wrong
In much of our everyday usage, the term means something more or less analogous to the way that we speak of an object being authentic – as the genuine article, not a copy or a fake. We think of people as authentic when they’re being themselves, consistent with their own personality and without pretence or pretending. And when they’re being reliable and trustworthy, generally resistant to the whims of the moment or the emotional approval of the crowd. In other words, when they show themselves to be stable and consistent over time and in different circumstances.