> So we need GR to even explain the non relativistic orbits.

GR is not the only theory of gravity that gives stable orbits.  (See
"Einstein Plus Two" by Petr Beckmann.)  In fact, GR assumes stable orbits as
part of it's derivation.  (It doesn't derive them.)  This results in the odd
situation of a physical portion of GR (finite speed of gravity) being
countered by solely metaphysical-magical-miraculous "velocity-dependent back
action" that no one can describe or explain in a physical sense.