I suppose that it is possible that I am misinterpreting what Sandokhan meant, and that he meant that UA is caused by circular centripetal force, like when swinging a bucket around, and the water stays flattened against the bottom.

If this is what he meant, then perhaps it is possible that the Earth is the bottom of the bucket, moving at a constant speed around the circle, with a 9.8 m/s/s imparted in g acceleration.

Yes, this is what I think JSS and I meant when we suggested rotating the Earth. I think the math would work for this version, but I’m worried about the previous version (see your penultimate post).

In the previous version, then the translational speed still increases, and so this wouldn’t fix the relativity issue.

I think one interesting consequence of the “bucket Earth” is that it should impose a constraint relation on the uniform circular speed and the radius. That is:

g=v^2/r.

Since we want to feel g on the surface, then the square of the speed divided by the radius of curvature must equal this value.

Do you have any thoughts on what either of these two values might have to be, roughly?