Thank you so much for your comment Sieran! I relate to a lot of what you've said here, also being a small-statured and quiet trans man who works in a field filled with predominately women. Most of the professional spaces I've occupied have been explicitly feminist spaces where women being in leadership positions, calling out sexism, and complaining about men was common. And of the handful of men who do get hired in my department, nearly all of them are gay and communicate in very feminine-coded ways.
Before I transitioned, I think this gender breakdown and culture insulated me from experiencing much sexism, and it's benefitted me immensely afterward, as well. There's very little overt competitiveness or pushiness in this environment, and when I do assert myself, people value my perspective and also don't feel like they have to put their guard up around me.
Sometimes effeminacy makes us less threatening as marginalized men, because it reads almost as an effacing of our societal power I think? And I think that might be a factor in both of our experiences.
Outside of work, I have gotten to know a lot of straight guys, some of them very masculine and from hyper-masculine cultural milieus -- but I've found them to be surprisingly tender and vulnerable around me. A big construction worker commented my perfume outside of the pharmacy the other day, and another guy on the bus told me all about grieving his son who passed away many years ago. I don't know what it is exactly, but I do think that my smallness and effeminacy actually can make even men feel more warmly toward me, and like they can drop the masculine posturing, and many of them seem to be desperate to do it.