Hmm. It feels really weird to self-identify as a "success story," but I think mine could count! I was in therapy for several years about a decade back, and it was extremely helpful--it certainly didn't "fix" everything, but the tools and insight I gained in working with that therapist were life-changing, and gave me what I needed in order to move forward and grow in some important ways. I wouldn't be the person I am now if I hadn't stuck with it. My issues weren't simple or small, and my life is still complicated and difficult sometimes (...isn't everyone's?), but I've been able to experience a lot of happiness, connection, and accomplishment over the years that I credit in part to that experience in therapy.
I also empathize tremendously with how frustrating it's been for you to try to find a solid therapist, and how many really unacceptably bad experiences you've had. I'm back in therapy again, looking for help working on both old stuff and new stuff, and only managed to find a new therapist who's a good fit after many attempts, some of which went on for months and cost more than I care to think about, some of which left me worse off than before. Part of that was my stuff, but part of it was also poor fit and lack of skill on their part. By the time I found my current therapist, I had half-decided I was just incapable of finding someone helpful again, that I was too resistant/complicated to connect effectively with any of the therapists available to me, that things were okay enough without therapy and I'd just have to figure out the rest on my own, but the guy I'm seeing now is SO much better than the ones I didn't click with in the past. Like you, I suspected I needed someone experienced, and that turned out to be correct. My current therapist certainly isn't perfect, but the contrast is immense compared to others I've worked with who were fresh out of school, whose modalities felt more superficial, and/or who lacked meaningful experience with people who share some of my identities/issues. The process of finding the right person is painful and stressful and often just awful, but ultimately worth it. I know many, many people who have benefitted tremendously from therapy and are doing really well.