I think there's a lot here to unpick.
Firstly, dressing children in gendered clothes is fine. It's not for me but there are certain advantages. Like not having to correct gender a billion times or having robust lasting clothes if a boy or bright easily spotted colours if a girl.
Dressing gender neutral is also fine too. I tend to opt for this, but I do have some dresses for my girls and interest clothes for my boys(why is it always bloody vehicles! But that's what they like)
I would dress either in a princess dress if they asked for it and have that available as a dressing up option.
But I wouldn't put my boys in frilly or a dress clothes. Pink girls clothes fine. Cute animals. Fine. Cut for a girl or dress. No.
The reason being is twofold. Firstly I think it's important for males and females to be able to see that they can like gendered things if they want. That a princessy girl is not lesser for example. I do want all clothes to be practical and comfortable so tend to shy away from boys and frills anyway.
But also, I can't expect my child to lead the way and be a target for bullying because I think things should be for everyone. That's for adults to do. So my husband is happy to wear a pink t shirt and is leading the way with that so am comfortable for my son to do so. We don't think it's fair for children to lead the revolution.
With nail varnish I don't really wear it much. I wouldn't suggest it to any of my children and whilst if my son asked for it i would allow it, I'd not actively make him to prove a point.
Also, me and husband are very clear that boys can't change sex if in proximity to sparkles. Many parents sadly push gender nonconformity on children then insist they are trans. I'd hope this wasn't the case as not conforming to stereotypes is fine for children.