My statement was too strong. By "knew" I meant that it was pretty likely that strong cosmic censorship wouldn't work out [1]. In addition, I think QFT and GR are both probably broken in some way given that they're incompatible and that no one has coerced one of the theories into working with the other. That feels like evidence that the problem is not as simple as just rejecting QM or GR to me. But again, calling that "knowing GR is unphysical" was too strong a statement.
[1]https://en.wikipedia.org/wiki/Cosmic_censorship_hypothesis