Your story is inspiring man, mine is similar too but instead of going to gym I take boxing classes which made me more confident I would talk with my friends, coaches give advices to juniors and take advice from seniors, basically it made me more sociable, gradually I used to talk with more strangers like saying good morning, after that my confidence was sky rocket like boom ,I didnt even took speech therapist classes what I did was read aloud books and started speaking slowly in time I adapted speaking slowly, now I hardly stutter, like I still stutter and I know that it's gonna be with me forever, but man it's like I can speak like non stutters like I only stutter while pronouncing words which are explosive like b, p but also it is rarely, man I am confident now I give speech in my college infront of thousands of people. I can relate with your story man it's purely inspiring for everyone like us. I wish you all the best in your future brother❤️