Bottom line: I think it’s early in the game to be making final pronouncements about what cosmological models are correct.
I once wrote Jason Lisle about experiments on alternate formulations of relativity. He didn’t seem interested.
I believe there is credible experimental evidence of variability or preferred directions for the speed of light. I actually found one paper in Physical Review Letters that may have found an anomaly. I’m having to re-learn some Special Relativity first so I could understand the issues better, and there are some things not talked about in curriculum like Fresnel drag where there have been alternate interpretations of Michelson-Morely and improved interferometers that leverage Fresnel drag.
So far Reginald Cahill of Flinders University seems to raise good issues, and I personally, but unsuccessfully tried to replicate his 2008 interferometry experiments.
I mention some of what Cahill found here along with some of the teaching materials on SR that I’m trying to develop: