We all have a personality and it IS who we “really are.” We also all have the ability to construct personalities that misrepresent our inner lives. Doing so creates a certain kind of stress and relieves other kinds of stresses.
Over the course of our childhoods we experiment with personality, and discover the elements that allow us to have stable and satisfying dealings with the world. We may cultivate several different personalities— each of them the real us in some respect.
Of course there are many elements of personality that are autonomic or otherwise habitual. That doesn’t mean personality is somehow not real.
A con artist or an actor can don a fake personality, but all that means is they are telling a kind of systemic lie to the world. This requires a lot of energy to maintain. Your real personality is that which minimizes required energy.