Most of the fediverse is male, and there's a significant trans woman space, but there's no spaces that really cater to cis women or to trans men specifically that I've seen.

And yes, I think it's reasonable to look for a space that is strongly (though not exclusively) cis-woman, in the same way that a Protestant would feel out of place in a Catholic community, even though they're all Christian. I imagine most cis women feel the same way as I (a cis man) feel when going to blahaj - like a friendly, allied visitor in a foreign land.