as i understand it, cultural appropriation is not an inherently bad thing. It often is, when black creators are overshadowed by white copycats catering to cracker audiences, when indigenous art is stolen in colonial contexts or when sacred traditions get turned into commodities. but all culture is appropriative to some degree, that kind of exchange is just part of cultural production, and it can be done respectfully when you try to learn about the culture you're taking inspiration from and treat it in a dignified way.

there's some disagreement about that ofc, some would argue to just let black people from the caribean tell new zombie stories. but i'd say if you avoid racist stereotypes about voudoun, if you understand and pay hommage to the original folk tales and their religious context (voudoun is, after all, a religious practice that is still alive both in west africa and in the diaspora) and when you take that as a starting point to develop the genre of zombie fiction further and use your position to shed more light on its often overlooked origins, there's nothing wrong with that approach.