What u/GreatRedYeti said.

Perhaps psychiatry might be the best fit, but not for the reasons of treating only men. You'll learn a lot about female nature when you get one on the couch; this knowledge can be useful in treating both men and women.

I mean, you'll be in the enviable position of getting paid to do the things for these women that boyfriends, beta orbiters and husbands pay to do for these women, thereby relieving men from having to do the shit work of hearing her nag, bitch, complain and obfuscate.

That will help men the world over a whole lot more than anything else you can do for them.