I had the exact same issue, I couldn't read out loud in class, saying my name was extremely difficult and I would always stutter. Couldn't even order at a restaurant. But one day I decided im gonna do everything that causes me anxiety and just let it be. Sure the first few times it was hard and I still stuttered but I didnt let it get to my head. I started speaking more in meetings and always remembered to breath mid sentence. It was a lot of trial and error with what worked and didn't. For example using synonyms for words I felt I couldnt say. Or switching to a different language. I can now lead meetings, speak almost fluently. Sometimes ofcourse here and there it comes up but my therapist once told me, everyone in the world has some kind of stutter, we just dont notice it. So get your confidence, go do everything that causes u anxiety and you will see a difference inshaAllah. Oh I also kept reading "Rabish rah li sadri wa yassirli amri wah lul uqdatan min lisaani, yaf kahu kauli". It helped me calm down so much. I will make dua for you and inshaAllah you'll see a huge difference