[Thatcherite]

Problem with your contention is that other civilisations with no interest in the bible also worked out that the earth was approximately spherical. The Columbus thing is a canard; no educated medieval european believed that the earth was flat (it is a modern myth largely propagated by US creationists as far as I can see that they did), and in fact Columbus was completely wrong about its size; he and his crew have died of starvation and thirst before reaching the indies if the American continent weren't in the way, which he couldn't have anticipated.

Numerous easy observations available for example to any mariner show instantly that the earth is a sphere. Its approximate size was calculated to reasonable accuracy by the ancient greeks and ancient egyptians amongst others. But Columbus took no notice.

Further, many biblical verses are at best ambivalent about the geometry of the earth. Amongst many examples that wouldn't help your case Satan shows Jesus all the kingdoms of the earth from a high mountain, possible on a flat earth and impossible on a sphere.

[Sun]

3,000 years ago the Bible said the world was round. It is very clear: Isaiah (40:22)

Actually atheists tried to ridicule religious people by CLAIMING religious people thought the world was flat, which was not true.