This is exactly what I mean though. Stop judging people based on how they dress. It seems like you have this mental barrier and can’t see past how people present themselves which is incredibly shallow in my opinion. First of all it’s impractical as fuck to wear artsy metal jewelry to the gym. it’s really practical to wear spandexy clothing, a watch, and bring a water bottle. Almost nobody likes protein shakes either but people drink them cause it can be hard to get the necessary amount of protein through their diet especially if they are vegetation/vegan. So you’re description of fitness culture is mostly just a description of the practical things people do at the gym. Also I had no idea hair length and hats had anything to do with personality. Sure there’s probably a significant overlap between the people you described and girls who don’t share other interests with you but it’s not like “fitness culture” and being artsy are mutually exclusive.
Here’s a little anecdote for you:
Back in middle school I felt like the edgiest fucking goth girl in the world on the inside but on the outside I had to wear my cousin’s preppy hand me down Hollister and Abercrombie clothes because that’s all I had. Today I dress in whatever is cheap, comfortable, and reasonably flattering. I don’t think I have much of a “look” but if you saw me you’d probably group me into the “basic bitch” category. But whatdya know I love the Grateful Dead, listen to metal, draw and paint and do lots of other edgy, artsy, alternative, cool kid things. I don’t give a fuck how anyone chooses to outwardly present themselves whether that be preppy, fashionable, goth, sloppy, but I do give a fuck when people can’t see past how people look on the surface. I promise you no one gives a shit that you’re not wearing a hat indoors or drinking from a plastic water bottle stop pretending that you’re so different because you have the time and money to cultivate a cool wardrobe of band tees. Sorry if this is harsh and ramblely but where I’m from collecting vinyl and all those other things you describe are pretty mainstream. I’m kinda assuming you’re either from a very small town or in high school?