Can i recommend you talk more about the original anime and the game idea? perhaps you might find here artist and programmers willing to help at least with the demo until you can start a kickstarter/crowfunding campaign and use then that money to hire artists.
IDK, is just an idea.
BTW. I don't recommend using AI if you are not artist or programmer, talking by experience using SD 1.5. (control net and Krita + krita ai diffusion) and chatGPT/Geminy in programming. Trust me, AI don't replace the professional it just a tool for the professional to use. You might be able to create a small prototype with AI but if it scale, AI alone become useless.
perhaps you can also create a small demo with free assets from here?https://itch.freezing.top/game-assets/free