I'm sorry that you've had no luck after all those treatments. I've never heard of the surgery you mentioned, but agree it does sound kind of scary! I also have a retroverted uterus, but my RE says that it has no impact on fertility (they're common enough that if it did, there would be way higher rates of infertility out there).
That said, the bloodflow thing isn't crazy. So much stuff that is supposed to help with ttc is all about getting bloodflow to the uterus (baby aspirin, acupuncture, yoga). If you are worried that this is keeping you from getting pregnant but don't want the surgery you should look into Mayan abdominal massage. I know of several people who's retroverted uteruses were reversed through the massage technique, which is pretty crazy when you think about it! It's just massage, so it's not invasive and should be much mildger on your body than surgery. Hope that helps, and good luck.