I haven't personally tried creating or selling male cologne, but it's definitely an interesting niche to explore. There's always potential to make money in any industry as long as you have a unique selling point and a good marketing strategy. If you're looking for some fragrance inspiration, you might want to check out bestmensfrag.com. They have a great selection of men's fragrances from top brands. You might find some fragrance ideas or enjoy reading about the different scents and their unique qualities. Good luck with your exploration into the male cologne niche!
It seems like a "niche of the niche" niche, but of course, if you've tried it and found some success with your local SEO efforts, why not aim higher after a while?