Itchy anus/lower vagina (on the vulva) for months, i've been to the doctor and tried everything from yeast, hemorrhoids, bv. literally everything :(?

Itching: Consider trying Nystatin topical ointment to treat for a fungal infection in the skin. Also consider albendazole to treat for pinworms. Both can cause itching in that area.

Biopsy the area: Chronic vulvar itchy is not a rare issue. If common approaches do not work then a yeast culture should be done as well as a biopsy of the vulva. Lichen sclerosis and lichen simplex complex are two common disorders that often get missed. They can be confirmed by biopsy and treated with Clobetasol.