"Fake it till you make it" (or "Fake it until you make it") is an English aphorism which suggests that by imitating confidence, competence, and an optimistic mindset, a person can realize those qualities in their real life.
To me, people who use this concept are saying "I don't have to learn anything or apply myself or work hard, I'll just act like I know what I'm doing to fool everyone into thinking I'm competent."
I would respect someone more if they said to me at my job "I don't know everything, but I'm willing to learn and work hard to get there.", then someone who tells me "I know what I'm doing, I've got this.", then proceeds to show me that they do not "got this".
I'm glad I am not someone who is in charge of hiring people....I don't know how they weed their way through all the BS in job interviews to hire the people who actually have competence, instead of those who "fake it 'til they make it!"