The natural levels of estrogen in women are already optimal, so there is no need to increase them. However, you are right there - estrogen is indeed the responsible for ladies' endurance. But it works differently in men, causing side effects, which does not happen in women. But as a matter of fact, testosterone is naturally related to estrogen in men, and the higher the levels of testosterone, the higher the levels of estrogen.
However, if you want to supplement with something for endurance, then Cardarine GW and SR9009 is definitely a good idea.