The problem is the popular definition of the term “authentic” – which is NOT “original”, unique, true, or “special”. (you snowflake you)
Authentic is supposed to express:
Self-done, Self-made, Self-created, Self-origin-ed.
So being authentic is a degree of how close one’s character matches their personal ideal self/ego. What makes them happy is getting closer to who they (maybe think) want to be.
And there is the rub. The goal of ideal self, or ideal ego – what you want, and why you want it. In knowing “Who you Are”, is somewhere between “how you were made”, and “who you were meant to be”.