"Being yourself", authenticity, and direct/brutal honesty are roughly orthogonal; you can (or not be) one without affecting the others. They are not the same thing.
Being not yourself takes energy and focus. Being yourself is free. It's also multiplicative: the amount of effort you put into something that's in alignment with yourself goes much further than effort put into something not in alignment. It's also restorative: doing things in alignment with yourself can restore energy and focus.
You don't need to determine the magic single identity that is yourself, or the magic single principle that defines yourself. Those don't exist; you just need to go "fuck it, I don't need to spend the effort to be somebody else; myself works just fine."
Being not yourself takes energy and focus. Being yourself is free. It's also multiplicative: the amount of effort you put into something that's in alignment with yourself goes much further than effort put into something not in alignment. It's also restorative: doing things in alignment with yourself can restore energy and focus.
You don't need to determine the magic single identity that is yourself, or the magic single principle that defines yourself. Those don't exist; you just need to go "fuck it, I don't need to spend the effort to be somebody else; myself works just fine."