Overthinking it. It's another ploy and it has to do with which "type" of the opposite sex they imagine themselves being. The MTFs who are "gender critical" think of themselves as a wise feminist crone, like Fred Armisen in the lesbian bookstore skit. Raven hair and ruby lips, sparks fly from her fingertips. Ohhh ohh, witchayyy woman.
If they were truly "gender critical" they'd stop cosplaying and act like a normal person and keep their fetish shit private.
Its larping all the way down isnt it? Even gender dysphoria itself is just a subconscious awareness of the dissonance between their idealized self, and the picture others form of them in their minds(which they can't even know, but can certainly guess at with some accuracy).
The internet is a disaster zone for these people because it allows them to roleplay their idealized self 24/7 with little or no pushback; worst case scenario 90% of the time is that they don't get the likes/amount of positive responses they were looking for. The other 10% of interactions, which could be categorized as genuinely negative, have their own little contingency plans; either de-escalate(ban/block), de-legitamize(evil nazi, right winger, fundamentalist, etc), or retreat( recede into the porn caked discord server kitten, retreat to the goon cave my fellow pooners). This little unspoken, but clealry undeniable, apparatus works to gaslight them into believing their real selves are the characters they play online, to the point that the online persona transcends to the real world in the most uncanny ways.
The "gender critical" troons are, like you said, still just playing a character they've contrived in their minds. One has to wonder if they're actually any closer to escaping the little hell they've created, or if they're just another layer of cope into the delusion. It might just be another form of masturbation, because that's all their lives are; masturbate to gender affirming porn, masturbate in the form of affirming feedback from other troons, masturbate by consuming tranny positive media, masturbate by daydreaming about your idealized self, mastrubate to the mental image of your idealized self, and on and on.