Oh, Break. This is a so tough topic.
I also really admire people who are confident. I'm not necesarily feel more comfortable with shy persons. Perhaps, bc I'm not a shy either.
I tend to feel comfortable with similar people than me and only if I see they accept me in some way. So, I can count them with the fingers on one hand. Thus, from time to time, I look for ways or clues to assurance myself if they really accept me or are comfortable with me. That stops me to be completely myself, even with them.

I see that when I have confidence in myself I can interact with people easily but then, I'm afraid of disappointing them and tend to withdraw unless I see some kind of assurance.
I guess it's a question of boosting self-esteem and never giving up the try to express as you are and going on with interactions. The most you avoid the most avoidant you become.

I think it's also very important to have an idea in your mind, people are all imperfect. Noone is better than you, only different and the same.