Science is about theories and measurements. The value of a theory is that it predicts measurements. Measurements are always approximate. But if measurements are close to the theoretical predictions, then it's a good theory.
As far as I can tell, Miller took measurements that seem to support theories about the existence of an ether drift to explain the constant speed of light. Today I don't think most physicists think the ether exists, but it might be worth looking into again. Whether the ether exists or not, relativity is limited in its applications, as Newtonian physics is limited in its applications.
The idea of "photons" makes about as much sense as the animal with properties of lions and elephants. When you see evidence of both waves and particles, the simplest explanation is that both waves and particles are present.
The wave/particle thing with light is probably similar to the situation for rifle fire in which waves moving at around 1100 fps are being created by bullets moving through the air much faster than that. The medium which light waves move through is probably a neutrino soup aether such as Wal Thornhill describes and the waves themselves move at a limit value which is C. The particles are probably Ralph Sansbury's sub-electron particles and the speed they move at is as Sansbury describes, around 10^22 m/sec. That would get you to one of the near galaxies in a couple of seconds.