I might get downvoted for this but I’ve had 3 episodes of stutter my whole life with the most recent one lasted more than 3 years. I tried MDMA, and it somehow relieved so much of my anxiety allowing me to achieve fluency. No one would believe that I have a stutter if I tell them right now. I’m not advocating for drugs because there are obvious risks, but if you’re desperate, might as well give it a try. I can’t promise that it will work for you, but it did for me.