That's starting to sound a lot like a religious belief.
That is quite the leap. Can you explain the reason why Einsteins equations predict things so well if they are not correct? Why is it so good at explaining observations?
I'm not sure why there's so many evangelists who feel the need to defend it so hard. There's as many head scratchers as there are "proofs". And then quantum is just not even close.
Most of what you call headscratchers are not even problems. It is how things work. Time and space are related, and perpendicular to each other. Quantum field theory is quite verified.
So clearly it's an incomplete theory at best, at worst completely wrong. There's been lots of scientific models historically that predicted things well enough but ended up in the bin.
To paraphrase - if you find a different explanation for some phenomina used to prove relativity, it doesn't matter. I'm right and you're wrong and there's nothing you can do about it.
To be more accurate it is if you find an explanation with more accurate predictive capability, after observing something the current theory does not predict. You can't, so it stands.
The current theory has made it so we have to believe in dark matter and dark energy, things we can't observe, because then the equations work out. Prediction didn't match observation.
Except their effects have been observed. Observing those effects has actually helped confirm general relativity as dark matter has been seen warping space.
"Observing the effects" is just a clever way of saying "it must be there, otherwise our equations are way off". They might as well call it The Force that holds the universe together.
That is incorrect. We have observed dark matter separate from regular matter. When galaxies collide the dark matter continues past, and causing gravitational lensing without matter.
[a classical explanation] "does not in the least diminish the conclusiveness of the experiment as a crucial test of the theory of relativity" - Albert Einstein (scientist)
It predicts stuff pretty well locally but on a cosmic scale the numbers get funky, you start needing string theory or dark matter to fix the equations. Then there's quantum mechanics.