Why is a quantum theory of Gravity even necessary?
If Einstein is correct, as observation has demonstrated so far, then Gravity is not an attraction between masses, but rather a warping of space by the respective masses.
If quantum scale particles lack enough mass to warp Space-Time, then gravity is simply not an issue.
Particle interaction can be explained in terms of field interactions and wave functions.
Call me naive.
But if Gravity is Not a force, but an effect. Then no “grand unification” is possible. Gravity would really have nothing to do with field strength, mass, charge, wave form, spin, or measured position.
Once the mass is known, then the gravitational effect becomes an effective constant in function much like C, the velocity of light in a vacuum.
As has been demonstrated, C , has in fact been variable depending upon calculable factors. My thought is Gravity is the same in effect.
Treat Gravity , much as Friction is accounted for in motion along a slope.
Isn't that effectively what both Einstein and Newton did?
Just a random thought.