In my experience and opinion getting outside of your comfort zone and actively engaging in situations which are uncomfortable speech wise and ultimately overcoming your fear is the only way to really therapize your stuttering successfully. I did a lot of speech therapy throughout my life but always made the mistake of mainly engaging in social activities with people I was already comfortable with and in situations in which I was not comfortable not/barely speaking. The result was that none of the speech therapies were really successful even though they in theory gave you very good tools to get more fluency. But what good is the best fluency tool for you if you don’t/can’t apply it in situations where it really “counts” because you simply can’t talk out of fear? I know that getting out there and exposing your stutter is among the hardest and most uncomfortable things many of us can imagine. But unless we want so live a secluded life and only talk to people very close to us for the rest of our lives (which would be perfectly fine), I feel like it’s the most important part of actually getting more fluent.