How do you explain the mounting evidences of double images and observing the same event twice (or more) with exactly the expected delay by grav lensing?

Anyhow, no new physics ever went against the old math, it always just adds corrective terms. Any new mathematics will need to be able to make the same predictions as GR in the limited cases of whatever this new limit will be (small distance or something?)

The old saying that "Einstein proved Newton was wrong" is a gross misunderstanding. A nevessary base principle for GR to be accepter was that it reduces to Newtonian mechanics at low speeds.