My stutter is moderate, I think, but my blocks are super strong. I do think the statements you listed does affect my stutter. For instance, if I’m in an interview or scenario and I’m very nervous, I stutter so much. In an interview or scenario where i genuinely don’t give a fuck, I’m so fluent that I’m soo shocked, that I had that in me. I had a 15 min interview( I didn’t give a fuck and was calm in the room), only had like 5-7 blocks. I find that repetition works really well for me. I work in sales and most interactions follow some formula in my head and I follow the same script. I rarely stutter (if I’m not stressed). I think breathing exercises do work for me, mainly because it calms me down. However, this is my anecdotal experience and I recognize that these might not work for others.