You state that: "you never see the two-body-problem treated in literature, neither for specialist nor for laypeople. It's always a one-body problem (black hole) or a central star with a tiny companion (perihelion-advance of Mercury)"

Yet, in this very article:

"the Hulse–Taylor binary, a PAIR of objects — a pulsar and a neutron star — spinning around each other. The time it takes for them to orbit each other has been decreasing, showing they’re losing energy, and this matches what’s expected from gravitational radiation. The work won the Nobel Prize in Physics in 1993."

And:

"When TWO massive objects — like black holes or neutron stars — merge, they warp space and time."

And:

"The first direct proof of gravitational radiation came on September 14, 2015, when the LIGO detectors measured waves from the collision of TWO black holes about 1.3 billion light years away from Earth. This discovery supports what Einstein and others predicted and opens up new ways to observe and understand gravity and events in the Universe, including the Big Bang. The formation of neutron stars and black holes also produces detectable gravitational radiation, leading to another Nobel Prize in Physics in 2017."

So, if "The 'explanation' of gravity by curving spacetime is nonsense", what's your explanation, Mr. (not Dr., I notice) I'm-Smarter-Than-Einstein-And-Two-Nobel-Committees genius?

Reading (and thinking) before typing.

Reading (and thinking) before typing.