the transfem blahaj community has about 3,600 users, this one has about 600.
Its a pattern I've noticed on online platforms. The trans population's gender balance tends to be the opposite of the site's cis population. The fediverse seems disproportionally male generally, so it tracks.
When I discovered I was a trans woman my instinct was to look up the trans communities on the sites I already used. I didn't reevaluate my entire internet habits holistically, and switch to female dominated platforms to match my new identity. I get the impression that's what most people do.
I'm not surprised to read that bluesky has more transmasc content. Whatever platform has more cis girls will probably have more transmascs as well, at a guess.
Its probably not for the best for trans people to be on platforms dominated by opposite gendered cis people, but it seems like an inevitability of the internet.