The best interactions in your life are not characterized by confidence but by comfort. When you are with the best people in your life, these moments are characterized by comfort and ease. When you see a three-year-old running around and saying hello to everyone, they do not do it out of confidence.
What you need to ask yourself is not how to gain more confidence to feel at ease but how you can change your perspective on others, how can you relate enough to realize you don’t need any confidence.