I can recognize myself exactly in what you describe - I felt like that for more than fifteen years, even while I completely repressed my gender dysphoria. For me, nothing worked; I tried everything from religious activities (helped me in many ways but didn't do much to my libido), to intensive exercise (just made it worse), to just "getting it over with" (hated it, but at least it gave temporary relief). At the end of the day, my libido was just as strong, and made me feel just as bad as it ever did.
I've now been on Spiro for three weeks, and while my libido hasn't really decreased, I'm already feeling better about it. It is slowly changing in nature, and less "overbearing". I'm slowly getting to a point where I don't really want it gone anymore. I do of course hope it keeps changing in the same direction, as I'm far from "there" yet.
To your questions about effects of anti-androgens and estrogen, I think the answer depends on your physiology, and my doctor refused to make any predictions with me, as some experience a drop of libido, others a change, others no effect at all. As with everything else related to effects of HRT, your mileage may vary.
I'd also recommend staying away from herbals. If they have any effect at all, their mechanism is often not known, and can be just as risky as, or riskier than, prescription drugs.