The only thing that ever helped my speech anxiety was doing a program and learning techniques to stutter less. It's a constant reminder when I have a stutter threat or a scary upcoming situation that I stutter and it brings anxiety. Then I think of a technique I could use and my anxiety slowly diminishes. Especially if I use the technique successfully then my fear meter drops even more. So that's what helped me. I'm sure some people just straight up accept their speech and that helps them too. I accept my speech as it is but I am always trying to improve which reduces my anxiety. There's nothing worse than this process: knowing you have to say something that you might stutter on, then not actually having a plan to not stutter on it. But if you can come up quickly with a technique that might work and then try and implement it you may also reduce your anxiety as well.