I would recommend therapy if it is available. A good course imo is something that is a mix of desensitisation and techniques like soft starts and cancellations. I did a 2 week course when I was 18 and it changed my life. Completely altered my perspective on my speech and really helped me move forward. It didn’t make me fluent but it really moved the stutter out of way when it came to both my social and professional life. If you cannot get therapy a lot of courses are based on principles found in this book: https://www.stutteringhelp.org/sites/default/files/Migrate/book0012_11th_ed.pdf