Ok first of all it's my fault that I am single. I have the appearance and looks down, I've worked hard on them.
Also deep inside I know I am a great guy who can be a blast to be friends with, but around strangers especially girls I can't express myself. I can't demonstrate who I am or how great I am, I'm just not myself and turn into this quiet mysterious person.
If I can fix this, I know that I can finally have a shot at dating consistently.
You haven't learned to be yourself and that is secondary to being insecure. Despite everything you say you don't have your act together. Hopefully time will help but time takes time so give yourself a break and learn to relax
I would practice some talking points in the mirror or something then just push yourself dude! Like literally just start kicking yourself into gear. You clearly know what the problem is so just try harder. Calm your nerves, take a deep breath, and just talk. Maybe get an alter ego like how Beyonce turns into Sasha Feirce.