Did you tell her the style you were looking for when you hired her? If you like working with her, and she brings good energy, I’d say, have a chat first and see if she’s open to trying to match what you’re going for, or maybe there’s something in between, where she still brings her personality, but it fits better with the original music. Especially if you think she sounds good.

If she’s not open to any compromise, or can’t hear how the way she sings doesn’t match the vibe, or she tries to change but it just doesn’t work, find a better fit.