From what I’ve read, you can have any discussion you’d like on trans people as long as it doesn’t call their existence as trans into question.

If you doubt people can be trans, then there’s not really a discussion to be had on the matter. Discussing whether Chinese people exist is strange, kind of xenophobic, but ultimately a dumb discussion. Discussing what falls under who is classified as “Chinese”, now that’s a discussion with some varied viewpoints and historical backing. In that same vein, you can discuss what constitutes as trans, you can talk about potential mislabeling of trans characters or whether a character was intended trans (think hindu gods, multiple “versions” of various myths might point male or female and that has to do with cultural understanding and historical spread and a million other things).

If you’ve already been banned like 11 times on reddit, have you considered that you may not be discussing a topic so much as just stating hateful rhetoric and opinions? There is a distinction between making a statement “no one can be trans” and posing an argument or topic for discussion “are there historical references to trans people”.