Im also 20m and at a similar point in my life. Getting into philosophy/spirituality has helped me a bit. At this point I've givin up on my stutter completely and just delved into a bunch of solo activities. Playing piano, reading, hiking, getting high, working out, etc. I'd say get out and experience life by yourself, so you dont have to stress about your stutter all the time. Everything about my life seems to be out of my control so its nice to let go once in a while and do things by myself. I wish i had better advice but all you gotta know is that you're not alone! Messege me if you ever wanna chat.