You apparently misunderstand the content of these theories. Kepler's laws can be derived from Newton's laws, they are essentially equivalent. Any calculation you wish to produce with either Newton's or Kepler's laws can be produced with GR. GR is the only theory that you need request. If you go back through the forum history, you will see that I provided with documentation on a model of the solar system that used GR, so perhaps go have a look at that and then come back and discuss?

Maybe you can actually produce what you state you have and then come back and discuss.

If GR was all there was to it, then Newton and Kepler go bye-bye...

Did you see anyone waving with a tear in their eye?

You seriously have no idea what you are talking about.

Newtons law of gravity works.

Einsteins GR generalized Newtons law with his theory on Special Relativity (spacetime), providing answers to issues observed while only using Newtons law of gravity.

We still do not need GR to simulate our solar system, but it easily can and is way more complicated to implement for something which doesn't really change the outcome in our small solar system.

Let me give a similar example:

When we throw objects, if we remove the friction of air, we generally calculate the trajectory via a parabola and this works fine.

However when we throw the ball, the ball actually follows an orbital path, which just so happens to intersect the earth because we didn't throw it very far.

Correctly, we should use math for an orbital path, but we use math for a parabola because there is only a minimal difference which is basically undetectable, and calculating a parabola is way easier than calculating an orbit.