First I want to agree with you on Einstein. He gave up on better defining time dilation to flow with more popular physicists. He gave up on the cosmological constant to acquiesce to Hubble. And he gave up on relativity when he used absolutist arguments against quantum mechanics. But there are certainly ideas that he exposed us to that have brought us closer to describing our observations.
I know I mention time dilation a lot, but it incorporates many of the same things you mention yet do not seem to like the term time dilation. Using the same model approach as Einstein, gravity is the effect of time dilation. My model considers the mechanic of it a drag on motion, not a curvature of medium. Again, similar descriptions.
In the spinning celestial bodies you mention, where the matter density is the highest there is the most drag. Yet this also fights the tendency for narrowing systems to increase velocity (right-hand momentum rule or "spinning ice skater).
Again, feel free to substitute "drag" everywhere you see me write "gravity" or "time dilation" and I think we are eye-to-eye.
Now I think what you are referring to in the sentence I highlighted is the two clock or grandfather paradox. Literally all of those thought experiments are garbage and, in my opinion, meant to intentionally confuse. Despite whether or not they make good math puzzles, they are disingenuous because, as you mentioned, they are trying to compare two separate things in different places or under different variables. Their different results are not a product of their artificial connection to one another ('c' speed limit theory), but their clear disconnection of circumstance being in completely different conditions of "drag".
I think you misinterpret my "Something true must be in all places at all scales" as being a not to relativism. It is not. Consider:
Metric expansion of the universe demands an outward flow of everything, except that there is no evidence of it and it contradicts everything we know about celestial bodies. But instead of looking for a better answer, they claim Hubble flow applies to large scales, and some other science to smaller scales.
Quantum mechanics appears to have a counterintuitive behavior to classical physics. I've even noted several violations to Newton's rules of motion. But instead of determining how quantum motion scales up to macromolecular dynamics, most scientists claim particles simply act different than large matter.
Einstein could not describe consolidated time dilation caused by relative velocity and that caused by gravitational influence, so we have general and special.
All of those items have been separated by scale or circumstance, but in every case they can be resolved to have the same mechanic at all scales. Theories other than metric expansion can show the same results and be compatible with observations down to the atomic level. Quantum mechanics can be scaled to galactic quantities and maintain the same results (not practical, but would show important correlations). Special and general relativity can be resolved to a common cause, with a single equation. that is why I believe certain things are more or less true, because they can apply at all scales. I can provide details and evidence to support these claims if you would like.
These are very complicated and poorly described things we are discussing. If you wish to be more long-form outside of medium, feel free to email me!