I think this is normal. At least for me, I spent my life basically masking around people I didn't know and pretending to be more masculine/normal/not effeminate. A habit like that is hard to break. And yeah it's harder around men because usually I'm a little more worried about them perceiving me as queer.

I don't really have any good advice, except my girlfriend is also trans, but has been out for a lot longer than me, and she definitely doesn't do the man mask thing anymore. So, I think it will just get better over time as you become more confident in your presentation/appearance and spend more time presenting feminine. By time I mean it will probably take years before everything feels natural. I'm sure spending lots of time socializing with other women would help.

But also maybe it doesn't matter that much. Like for me at least I see nothing wrong with being a "male socialized" woman as long as I am seen as a woman. And that has a lot to do with what I look like than how I act.