No, I'm not invoking the concept of an immortal soul, and it's incredibly frustrating that this is the go-to assumption anyone makes when criticism of AI's creative capabilities.
It's entirely possible to be a pure physicalist while also believing AIs aren't capable of creativity because they aren't capable of being human, and don't have the necessary human experience to inform the processes they simulate, because creativity is fundamentally a means of human communication. That isn't actually an argument from the supernatural, and unless you believe it's possible to derive a brain simulation of Hayao Miyazaki complete with his lived experiences and memories simply by studying the specific technical aspects of his animation style in aggregate, then I think the why of AI's limitations in this regard should be obvious.