bro are you seriously drawing every human sprite separately? how about just dividing the sprites into several parts and stacking them on top of each other? this will help in the future and reduce the weight of the game. but you really need to work on it, do you have enough time?
they're already divided into head and body sprites. I am not drawing the human sprites by hand, i'm capturing them in koikatsu character studio.
splitting the character even further with separate sprites for boobs/arms would be more efficient but not really possible with screencaps of 3D models because repositioning body parts affects shadows on other body parts. it's possible if I draw everything by hand, which i do in one of my other games
it's clear that there may be other ways. for example, you can manually draw the shadows, but it's quite a hassle, and I don't think you'll be doing that. Perhaps you should find someone to help you with your work, as there are many skilled artists and C# programmers on this website. I've looked at your code, and it's well-written. You've done a great job. However, there's something you need to do with the sprites, and it's crucial.