Just my ideas. I believe that the 26-D string theory of closed strings is the unified field. It includes tachyons for propagating the gravitational field almost instantly.
The unified field is the medium in which all them various forces and matter waves become the same and therefore can couple. Although I do not believe in particles, it is where for example the fields of photons can couple with the fields of electrons. This I believe happens when both the electron waves and the photon waves (actually EM fields) collapse down to Planck scales to become the unified field for an instant.
I believe that the same thing happens in the singularity region of a black hole. But like you I, nor anyone else, have the equations to predict such behavior. Rather, it is hueristic modeling of what a field only quantum physics must do.
An alternative is the particle only quantum physics of Feymann. He derived QED from photons, electrons and positrons coming back from the future and got the most accurate theory ever. I believe that the particle only theories are dualistic to the field only theories- only the field only theories are closer to reality in not requiring particles that go backward in time. However, it requires a collapse theory (unknown) that is something like inverse inflation theory.
Regarding Einstein's curved space. His GR assumes that space is instantly curved as massive bodies move about. So that if gravitons exist and carry the gravity force, they must considerable exceed the speed of light. That seems correct as such particles or fields must be almost instantaneous for black holes to exist. Otherwise the mass in the hole could not exert force on the matter outside the hole.
My suspicion is that the 26-D string theory will be needed to provide tachyons, particles that exceed the speed of light, for the speed of gravity to be instantaneous. It also suggests that the unified field is largely gravitational.
Your argument that aether calculations agree with GR because of double refraction is actually specious as you do not make any calculations at all. Newton believed in aether. So presumably his calculations are appropriate for your ideas in this case, and they are incorrect. You just can't make words and make such a claim. You have to do the calculations and the first thing is to find the effective dielectric constant of the aether.
I use yanniru rather than Richard as there are other Richards on this forum