Honestly have no clue. For me it really seems to be some kind of issue with gender norms or homophobia/biphobia, I did the whole work on/take care yourself thing in both looks and mentality, and started working out and eating better. As a result, the amount of attention I receive from gay/bi/bicurious men, as well as from bi and bicurious women has gone up dramatically, but the attention from straight women remains unchanged, basically almost none lol. I'm a bi guy with long hair and a beard that dresses a little bit different, but it's not anything crazy out there lol. However it seems that people still notice or can tell, maybe even subconsciously, even though I'm mostly in the closet.
I'd just encourage guys to be the best version of themselves that they can be (which means putting a lot of effort in, unfortunately), as far as their financial situation, work, and health allows, and go from there. You never know if you don't try and put yourself out there. I did (not through dating apps though), and think I discovered what I wrote about in the first paragraph. Which is very valuable information for dating in the future, at least for me.