It’s GREAT that you’ve recognized it’s based on anxiety. Took me 24+ years to accept that fact. The moment I did, my fluency took a 180. Like others said, acknowledge it’s just anxiety and not a personal defect. Everyone has anxiety, what matters is how we manage it. Trying to fight the anxiety by over pre-preparing, forcing yourself to fight the anxiety, etc. is near futile. Just chalk it up as “Eh, I’m anxious because I might stutter and that’s okay. It’s okay to be anxious, it’s okay to stutter. May as well not fight it and take my time getting the words out.”