You got isekei'd, and you see you're the only man in a world made entirely of immortal women of different species. But you yourself is also immortal. You can get them pregnant and the child will always be female, and when that female child grows up you can now get her pregnant. You can get any female child pregnant when they grow up. The entire universe contains females, your job is to reproduce with all of them, you can travel to any planet, universe, reality, omniverse etc, whenever you want.