A few years ago I happened on a podcast (can't remember which it was now) where gay actors were talking about the roles on offer. It was really interesting because it cycled through the different ways that historically oppressed groups are represented - so you start with the tragic victim portrayal (the Holocaust or slavery or the AIDS crisis); you move onto comedy (the flowering of black comedy with Richard Pryor or Eddie Murphy, or the ubiquitous gay best friend in 1990s romcoms); and eventually you get to the point where a minority can just play any character.
This would have been in the aftermath of BLM, because they were pointing out that it was the best time ever to be a black actor if you just wanted to get hired, but it wasn't that good if you wanted to play an interesting character instead of a tragic victim or soulful saint.
The point the gay actors came back to was - actors love to play assholes. Jack Nicholson and Bill Murray have built stellar careers on playing characters with no redeeming features. So the gay actors were saying, we're tired of playing Gordon Goodbrother, we're tired of being the female lead's non-sexual gay best friend, when do we get to play assholes?
(Kevin Spacey of course has been doing this for many years, but he's exceptional.)
So the movies I know with trans characters usually have them as a villain or a comic punchline, and I can see why trans audiences would hate that, especially if it's a numbers game and that's their only portrayal. But, assuming we want to move past heroic/tragic trans characters towards rounded characters who happen to be trans (I suspect lots of critics want to stop at heroic/tragic) then you'd need to have, let's say, 10% of actors being trans, and as a pure numbers game, that looks really artificial.
When you artificially inflate the numbers, even for the best of motives, it's really obvious. We're currently at a point where normie American TV viewers who watch detective shows are asking "how come three quarters of the detectives are gay all of a sudden?" And that's a much bigger minority.