for reddit theres mostly just transgendercirclejerk. all the other spaces are either super sexual (not necessarily bad, but the online horny posters are mostly terminally online and often early transition) or 4chan (not obviously bad by default, but comes with transmed worms that they claim arent transmedicalism)
i just wouldnt touch trans reddit tbh. bluesky is hostile to trans women but not to the same extent as other platforms and the culture is a lot more chill than anywhere else online. unfortunately, the high abundance of libs, strong block button, and weak right wing presence makes it the best place for trans women online.