It's my understanding that everypoint is essentially the centre of the universe.

and if you travel out from any point in a straight line you'll eventually arrive back where you started

if this is so could the universe be rightly viewed, from one perspective, as a sphere with radius of 13.8 billion light years, But the surface of the sphere is equally the same point in space time as the centre of the sphere.

if this is so, from the perspective of every point in the universe there is such a sphere around it. At the extremities of these spheres surfaces would overlap. Here, a repulsive nuclear force would simultaneously be an attractive force at the centre.

could gravitation and the strong nuclear force be one and the same, but skewed into 2 apparent forces because of curved space?

Peter