Reminder: Authenticity is in the eye of the beholder. It’s not your call, it’s theirs.
No matter how “authentic” you think you are, it’s their perception of your actions and words that counts: Do they perceive what you say and do as being consistent with how you say and do it?
Their perception is not in your full control – which is why I think that focusing on “authenticity” can lead you astray.
What’s in your control, though, is being true to your values and beliefs – which starts with getting clarity about those and being able to articulate them. Whether someone perceives that as “authentic” is a different question.