Thanks for your personal interpretation of feminism, described as fact, here is mine.
First, the guiding principle of feminism is not self-determination, it is female liberation. Secondly, gender critical feminists do not necessarily subscribe to blank-slatism either. I think it is an open question within feminism of "what would we even be like?" without the confines of patriarchy. We simply don't know.
I also disagree with you when you say that:
"Another example of transphobia being rooted in misogyny is how much more trans women are demonised & dehumanised than trans men particularly as being motivated by sexual deviancy & predation".
We don't demonise and dehumanise, we simply call them men, and refer to male-pattern violence, which does not apply to female trans-identified persons. Also,
"'trans people promote stereotypes by claiming the are the opposite gender' but even if they didn't claim they were the opposite gender we all know that despite what a natal male who expresses feminine presentation calls themselves it would still be socially unacceptable but not so for a butch natal female".
Not on our watch mate, and I think you know that most feminists are perfectly happy for men to express themselves however (within the bounds of decency and respect), but we do ask that you stop telling us what a woman is, and that you've become one.
Finally, "Now some might say that trans people promote sexist stereotypes by expressing traditional /feminine behaviours but don't cis women too? Aren't they 'promoting' misogyny too? Or are they 'let off the hook' for 'not knowing any better' as hapless 'victims' lacking autonomy?".
No, we are just trying to live our lives as best we can. We object to the sexual objectification of women, evident in many TIMs presentation. Actual women range from a very strong feminine stereotype alignment, to none at all. Some women judge others for their appearance, some don't. Female liberation is a huge project, and although we wish it was moving faster, and we would all feel comfortable enough in ourselves to just be without pressure to conform, that's not reality. It's best not to blame women as a whole for that. Some womens security and survival depends on it.