Zen is good for building self confidence. In Zen, you get to be the universe. You get to be Buddha. You learn that most people are living a life of delusion. From an ego perspective, this is all wonderful news. Understanding this will help you feel as good as anybody else and better than some. You may still admire different people’s particular style of delusion, but you will secretly know that they are all fooling themselves.
You know that you are fooling yourself too. This is helpful if you are prone to sadness and lack self confidence. Your worries are unfounded.
You can take all of this at face value, or, if you want to test it, you can begin a meditation practice. Either way, you can quickly boost your self confidence. If you are worried about yourself, you have nothing to worry about. Be confidence.