What if it restores the physical, but can't bring back the soul? Just a perfectly healthy empty body for an unsettling Monkey's Paw situation. Good for organ transplant surgeries since I fear using the ability on a live person would fuck their brain up.
Since it's an isekai, the existence of souls is a given in this world. Otherwise, a time reversed brain would still have the personality and memories before it died. Hmm...
I do wonder if there will be a point in the story where she "cleans" a dead animal back to life. But then you could make the point that animals don't have souls in this world's setting.
The inverse would be interesting to see, where all things have a soul of some sort (I think it's called animism?). It could then limit what she could "clean" as in torn socks might still have the soul of the socks, slightly damaged antiques too, while a dead fly might have already lost its soul hence it can't be "cleaned' back to life.
She could technically "clean" a now flattened mountain on which a humongous castle stood a thousand years ago if it was a plain time-reversing ability. I do wonder how her magic actually works and if it'll be ever fully explained in the story.
Edit: Or there could be an even simpler restriction where she can only "clean" stuff that helps her family or others close to her.