I mean, first GR is a semi-classical theoryt which makes BH neither classical nor quantum. And since it was formed from many particles so it seems in the least it is closer to classical(so no QM should apply) and I don't know if it makes sense to treat it as manyparticle nonrelativistic qft. Also we don't know if any natural quantum particle that is in the Planck's region i.e. no quantum BH exists. So BH does not generally makes sense physically.