Why does it matter so much if its authentic? What value does authenticity really give? I'm certainly not advocating for a wholesale change in your character, but it feels good to sometimes act out of character, or to curate experiences and present them to your friends (or the world, depending on what you seek)
But since they likely spend more time as one version of themselves - when no camera is pointed at them - and less time as the on-camera version, I'd argue that the latter is less authentic.
It's a bit like using alcohol (ie, the camera) as a crutch to give yourself permission to loosen up in social situations. It gets the job done but I'd argue it's not authentic.