Ok, but the assumption that the speed of light is constant is false, we can see gravitational lensing. Space has an observed refractive index that depends on depth in a gravitational well. Gauge theory gravity (see Chris Doran's paper: arxiv.org/abs/gr-qc/040…) works in flat euclidean space. For something without tensor notation, I like José B. Almeida's idea: arxiv.org/abs/physics/0…

The curved-space idea fundamentally is nonsense, that's not how spatial geometry works or can work on the most basic mathematical level. I think it was a psyop intended to derail physics.