Hey! I relate completly to your case. I also struggle with letters/phrases, and I also will try to switch out any word that I know I will have a hard time with. I am in speech therapy and it has helped my confidence, especially at work where I cannot really switch out words and have to say words that I know I will stutter on. I am still very self-conscious and have not gotten to the point where I can accept how I talk. I feel like a failure everytime I open my mouth. With that said, you are not alone in your stuttering journey and it was nice to see that someone else struggles the same way I do.