because nonbinary is being neither male nor female and transfem is being a woman, a binary gender. They are not the same thing.
Your definitions are overly simplistic. There are bigender people who are male and female and are still non-binary.
Male and female are mutually exclusive, people can’t be both male and female, that is asinine. They must be one or the other or neither, can’t be both, womanhood and manhood is mutually exclusive.
Do you have any reason to believe that, other than your intuition? Plenty of aspects of reality are unintuitive, and people, in my experience, can be even less intuitive than quantum mechanics. As non-binary identities go, bigender isn’t a contested one.
Consider giving https://nonbinary.wiki/wiki/Bigender a brief read, and checking out the references.
Fem and woman aren’t synonyms. How else would you describe someone who was AMAB but is librafem, isn’t a woman and even further from being a man, but still has a connection to femininity?
Lots of transfem people are women, but its sorta like a rectangle and square (all squares are rectangles, but only some rectangles are squares). Practically all trans woman are transfem, but not all transfem people are women.
A feminine gender identity is equivalent to womanhood. People who identify as feminine are also women to some extent even if they don’t call themselves women, this is especially true for trans women who are in-denial of their transness (i.e. people who claim to be femboys yet want boobs and pretty faces).
(This is incorrect.)
Since you say so, you must know what a gender identity is. Tell me then, what is gender? What principle makes something a gender, or not a gender?