>only men can crossdress
True
>most manly thing one can do
The concepts of manliness and feminity are already social constructs (unlike gender and sex which in my not so humble opinion are hardline facts).
So if we even are going to go with the normal stereotype of something being manly… assigning completely arbitrary qualifications to something being manly is a hard thing to do and starts to border on the line of lingustics and metaphysics, which is a whole nother can of worms.
Is something being manly measured by if only a man can do it like your image suggests?… perhaps if it requires the most testosterone to do successfully, or perhaps something manly is simply what we all agree on being manly/associated with men.
I think talking about a social label such as "manly" or "womanly" (girly?) It is almost impossible to assign definitive meaning.
If I had to choose I would say that something heing manly is a combination of many different arguable factors:
Men being able to do it, the inherent aesthetic appeal to standard manliness, the levels of testosterone, how much physical effort it takes to do something. The commonness that standard men adhere to it.
I love partial crossdressing. Tight fitting clothing, do my eyelashes up, occasionally put on a crop top or jean shorts. Love me some flowery cologne/perfume,and just generally put a lot of effort into my looks despite being a 5-6/10 on a good day. Hell I would even wear heels and stocking if I was around people who were cool with it, Girls sometimes ask me if I'm gay but I'm as straight as an arrow.
Fuck gender stereotypes, but also fuck transvestites.
Honestly feel bad for people who go down that slope.
Acting/dressing feminine doesn't make you any less of a man
Acting/dressing masculine doesn't make you any less of a woman.
You are perfect as you are, and already as mentally fucked up as everyone else, no need to go and make it worse by letting gender be a part of your identity.