It is technically true that transgender people as they identify today are gender essentialists. But that is because they are the result of a gender essentialist society. Gender is a social construct defining social roles and norms based on sex. When gender and sex mismatch, a person is transgender. That is the expected logical outcome in societies with strong gender definitions. Gender definitions have grown softer in the west in recent times, but there is still a lot of social pressure to be gender conforming.
Gender abolitionism is what it sounds like you are advocating for. If we as a society stopped defining everyday things as girl things and guy things then there would be less need for transgender identity because everyone else would not put them into buckets. There would still be a smaller group of people with physical body dysmorphia that would still feel that way though.
You can't call them the biggest ones though. Because the only reason it becomes a big deal is that everyone else makes it a big deal. Because people are worried about which bathrooms other people use or are worried their children might see a masculine looking person in a dress and ask questions.
