If you want to make money, make a typical waifu-collection gamblegacha game like most of the rest of the market has drifted towards. Hire an artist who can make cute girls and rake in the easy money. Only thing is you'd want to hire good artists and take some time to program it decently-enough to work on a wide variety of phones. Or just make it iphone-exclusive and not worry about any of the Android fractured userbase.