It's so common for women to dream of or fantasize being a gay male that there are psychology studies around the phenomenon, and entire subsets of media aimed at just that-- look at yaoi.
I'm in a really big roleplay community and about half (if not more) of the girls in the community roleplay gay male characters.
That doesn't make them trans, though. Being a man isn't about your desires or whether the grass looks greener on the other side of the fence. It's about having this innate knowledge that you should be male in all aspects; physically and socially.
My genitals are slightly more tolerable since T (I'm fairly big for a T-guy) but I still cannot even stand looking at them or having them touched. The concept of them being used in a female manner (penetrated) absolutely disgusts me. It has nothing to do with sexual desires and everything to do with, "my brain is telling me there should be a dick there". That's pretty much what dysphoria is.
Three of my exes wanted to be gay men and had the misfortune of assuming they were trans, only to detransition later when they realized it wasn't the case and they figured out it was just an aspect of their sexual fantasies.