I don't know if you like gambling(I mean speech therapy is kinda like gambling)or have enough money. If one therapy can't help, you can considering conducting multiple therapies so it's very not money-friendly. Overcoming or even just mitigating stuttering is a big conundrum among stutterers and that's why we need to set up organizations/communities for us. But I think if you can retrospect the occasions/conditions where your stuttering is mitigated either spontanouesly or with your own forces, you can simulate them everytime you are speaking to accomplish stuttering migitations. Like when you breath deeply your stuttering is mitigated, then you can try taking deep breaths to speak.