"Be yourself" is not wrong, but it's not specific enough.
You can be perfectly authentic, but that doesn't mean being socially uncalibrated.
Get good at being sociable, then blend that with your personal tastes and preferences.
I thought "be yourself" was fine until I grew up and learned I was just being rude to most people and called myself introverted when I didn't make friends.
So it's not useful advice for most that need to build yourself up to something that performs decently, nicely or awesomely (the most you can).
And Fake it till you make it is an awful expression (encourages posing and faking is legitimate when is not by definition) to communicate that you just need practice to obtain a level of performance.
What are you trying to make though? You're pretending to want the same things the people you think you need to fit in with want, but if you don't actually want those things, what point is there to be in a competition to get them?