Interesting idea, need more polygons though, or use a static img of a character and represent the act like many rpgm h-games do. I will keep a look on the development, good luck. o7
There are some ways that i know you could get your hands on free and with no copyright 3D models, i have noticed that AI have become better at making models though i think you would still need to rig and paint them, it is also a bit complicated to set up, there is also free models designed for VRchat even lewd ones that works on Unity that are fully rigged that you could try editing too, but that would also require some 3D modeling skills, you could also ask for help on forums, maybe someone is willing to join you on the project, who knows, MMD and koikatsu are also options for static img and customization, or just go full AI.