Speech therapy did nothing for me as well. Used to have and maybe still have adhd. I tried meditation but could not keep it up. Tai ji (tai chi) changed the world for me. The slow moving meditation lowers the rate at which my brain TRIES to process the world. Which results in more than just the reduction of my stutter. So much more. Also try to support a healthy microbiome. Like lactobacillus reuteri actually produces serotonin and is absent in most westerners/western diet. Serotonin is the feel good hormone which if absent will increase your anxiety.