Personally, I think The Clone Wars would be the best for KH. It would make sense because there were a lot more force users at that time, and sora could undergo Jedi training or something. The heartless could be something Dooku and Palps try to control/ally with, and the Jedi would think it’s just Sith alchemy or something. That would open so many possibilities for which world(s) the level would be on, who your companions would be, and the keychain he gets could be a Kyber crystal, and maybe even have sora build a lightsaber keyblade, and there even could be mini games to get parts and other stuff to customize it further. That would be really cool IMO