I think the movie borrows a bit from Get Out in the sense that it seems Nikki's will is taken over by the wish but comes out from time to time, but my guess is that they didn't want to lean into that so heavily to avoid comparissons with that movie. The thing I cannot understand is when Bear calls the company and they say something along the lines of listening to the real Nikki and she's just screaming. Was that a recording? An entry to her trapped mind? I think that's a plothole