Just be yourself is only good advice if you are an exceptional person. A lot of people's authentic selves are not efficient for their desired outcomes. It makes sense to hold yourself to a higher standard when you run into incredible challenge. Taking inspiration from others or a "super" version of yourself can be useful. Your authentic self also changes over time.

In interpersonal relationships it is better to be authentic, but I don't believe maximizing for authenticity has much value in business.