In my perception it is just a made-up things.

And here is why I think like that: through out the history "masculinity" and "femininity" were changing. Men were wearing dresses and make-up, women were praised for having a lot of weight, or feminine was having long neck, and masculine to have scars, and so on. Almost always biological facts were still considered as masculinity and femininity, but things like "men are strong and agressive" were not always considered as "being manly", as in ancient Greece - being smart or rich was more "manly" than being buffed.

So masculinity or femininity in general is a way to describe gender stereotypes of current age and current society. It can be useful to use those labels to fast describe yourself, but at same time it is damaging if used by "wrong people" (TRA for example).

For me masculinity and femininity as still tied with biology, and just synonymous to male or female. I have big bias in this, because I am "feminine gay man" and I was helping in PCOS support centers, but for me Butch lesbian or even woman with PCOS and face hair is still feminine, same as transmen, same with "feminine" men or super buffed men, they are both for me same masculine. However, that can offend some LGB people, so I am not often saying this.