The issue us that the hobbies you have have little correlation with whether or not women like you. I do many things on the list of hobbies that women find unattractive, but I don't have trouble pulling because very little of attracting a sexual partner actually has to do with having a lot in common with them. It's more of vibey thing like that guy was saying.
At the same time, the gym is gonna help self image and self confidence which will help you be fun chill and easygoing which will help you get laid.
As someone who does hit the gym, in my experience the majority of people you're impressing with your physique are men. Sure I'd say most women like it if you have it (assuming you aren't too big), but generalising that it's the main attraction would be a mistake.
The benefits of hitting the gym are much more than just getting swole. It increases self-confidence, helps to improve self-image, etc, which are all way more important to getting laid than any hobby you could have.
No. I don't think that going to a dermatologist causes significant hormonal changes like exercising regularly does. Why would I ever think that salicylic acid and antibiotics would affect my neurotransmitters and hormones significantly? They don't...
The fact that some derms offer hormonal therapy for certain cases of severe acne does not make that regular by any means. If you have a hormonal problem you go to an endocrinologist.
Hiking - sounds attractive, but the woman may not actually enjoy hiking especially doing multiple day trails
Woodworking - "wow you made this desk yourself?!" Reality: Spent weeks designing and getting the right materials, spent more weeks in the shop getting everything right, spent months all together away and in a shop so you could present..... a desk (the novelty runs out real quick with a partner)
Same with a lot of them, if you're really into a hobby and it is presentable.... You've spent a fuckton of time on it. Something you could do while you were single, 10x harder to pick up or continue doing in a relationship since your time is now divided. It becomes one of those, "Yeah they love doing photography and they're really good at it!" (cue partner standing there who hasn't taken a picture in over a year looking sheepish).
Oh yeah, equipment is definitely a perk. It's kinda amazing how cheap shop vacs are too compared to going to a car wash repeatedly. But I think you jostled a caveat to all of these hobbies, being not broke lol. Could really put a strain on a relationship when you would previously sacrifice to get something but now you're asking a partner to do the same.
"Playing and instrument", for example, is likely not a tender accoustic guitar in the moonlight. It's repetitive, monotonic, loud noise, that rarely resembles music most of the time, no matter the instrument.
Same with woodworking, it's not sculpting a figurine with a knife and a pipe in your mouth. It's FUCKING LOUD machines, wood dust everywhere (if you're a hobbyist), every nook of your place becomes wood storage.
Most of the "attractive" hobbies might sound attractive, when you don't really think about them and go with your first thought (that's mostly based on depictions in films/tv shows, etc.)