I can see where you are going wrong, I think you will find it surprisingly simple. You have not factored in expansion, which counteracts compression. There are a number of expanding factors involved when we are discussing the Earth, these include heat from within the Earth itself (heat causes particles to move faster, with a tendency to force them apart). This is why certain objects explode in microwave ovens). Another thing which expands the surface of the Earth is rainfall. As rain falls on as particular area of ground, the ground will become saturated and swell slightly. The Earth is sustained in perpetuity through balances such as these.
Wow, just wow. One last time then I'm out.
Point A has a measured acceleration of we'll say 9.81 m/s^2, and point B has a measured acceleration of 9.79 m/s^2. These values are shown to be
constant over time, they do not change. If those points start out near the same spot, and accelerate upwards at the values above, point A will quickly acquire a larger velocity than the other, and will move upwards with an ever increasing lead over point B, hence point A would not stay on the surface of the flat Earth for long, it would shoot off into space, and point B would sink into the ground. This is not happening, or we would see mountain ranges and chasms appearing in a matter of seconds.
In the real Earth, we don't measure any movement of those points relative to the rest of the ground, so no compression or expansion is happening. Therefore the Earth is not being accelerated upwards by some unseen UA, gravitational force is the only other option.
If you don't understand that, there's nothing else I can do for you.