After reading up to ch.7, I don't think this is about trans or lgbt thingy, mainly the difference between japanese and western interpretation about the word "girl inside(mental otome)", and the context I got from reading.
I think what the author is trying to convey, rather than the mc was a woman born inside a man's body, is more like that his aesthetics, interests, hobbies, etc., is something you'd normally find in girls. A girl's trait. Namely, liking cute things like plushies, dolls, accessories, girl's fashions, the list goes on. It's femininity, not really being a female.
But his mind is still that of a man. As he did mention he had a girlfriend(who also has the same liking) as well as he's a man inside. I don't think he would find himself a girlfriend if he's actually a trans. I haven't found any hint about him crossdressing in his previous life either. It's kind of something like, normal people(Japanese or any others) would be creeped out when a man has or talks about girly hobbies. It's not normal after all. They'd expect a man to be masculine.
And mc being reincarnated as a girl is, instead of saying it's trans, more like he no longer have to fear of others judging his preferences and can indulge in his dream however he likes, cuz it's no longer abnormal. Thus living the fantasies as intended.
The story also hasn't explicitly show him(her) trying to act more feminine like a girl as her main goal, only girly hobbies. I also noticed that not only did the mc not actively trying to make herself look more cute, she only did that to her subjects(dolls) and other people(the marquess's daughter), so far.
In the future tho, we can only wait and see.