Oestrogen therapy for low E2 levels - helpful / harmful?

[j_lipinski]

39F regular, ovulatory cycles, but sub-fertility with low E2 levels, vaginismus, vaginitis - intercourse is difficult.
Has tried Estradot for 3 months in the past, which helps vaginismus (intercourse), but still unsuccessful fertility-wise.
I'd love to give her herbs, but I doubt she'll get the same results.
So I'm wondering whether advising her to go back on the E2 patch might help in the short-term, but I'm worried, due to negative feedback, might affect her own endogenous E2 levels in the longterm?
I wouldn't want her to run into more trouble wrt fertility and her future possible dependency on exogenous E2?
Hope you can advise.
Thanks very much