Man I'm two years older than you and I feel everything you just said. My stutter is very severe, and I have mild autism, so I struggle with a lot of things in life. I spent all of middle and high school with zero friends and not alot of human interaction. I honestly wish I can give you advice but I'm struggling just like you are so I'm not sure what to say. The one thing that happened to me recently that I wish will give you hope for the future, is that I finnaly got a girlfriend after many years of being lonely. Luckily she understands me and we are doing well together. I was/am in your exact shoes brother. Just keep going man, you got this ❤️