Okay, I think I see what you're saying: things get weird near Planck scales. Under the hypothesis of quantum foam, spacetime is anything but flat at Planck scales. And since QM and GR don't play well together, GR isn't about to try and rescue anything.
I guess my original point though was that above Planck scales, QM and special
relativity are already together, so there's no point in taking a step backwards into Lorentzian aether. That was really my only point.