For all things philosophical.
Of course your own self confidence matters, however what also matters is competence in your chosen field. You can believe in yourself all you want, but if you haven’t got what it takes you will soon be shown to be the fraud that you are. Self belief will only get you so far, hard work and pure will power is what it takes to get the rest of the way, and even then you will be among giants when you are playing at the top 1%, you need to be someone special to be the best at what you do. Failure will soon take away the sense of superiority. You also need to know your flaws, and be self critical, in order to improve. If you have your blinders on you will keep making the same mistakes. In the end it’s up to you if you succeed or fail, but unless you have a higher purpose driving you there’s no way you can force yourself to be the best.
Ever tried SSRIs or MDMA ? Serotonin is great!