I took the time in the past to find a Hebrew word for sphere. There isn't one. There is a word for ball, but it also implies a child's plaything. In Hebrew, circle is the best word to desribe the earth.
But that's the point. It doesn't describe it; it is simply wrong. In fact, "large ball," even if the Hebrew for "ball" denoted a toy, would be more accurate, at least by analogy, than "circle." "Circle" is, in every sense, wrong.
This, of course, also doesn't explain the errors regarding the earth being immovable, and describing the earth's supposed "corners" and "foundations." Not to mention trees and mountains so high they could be see or see, the furthest reaches of the earth.
That these are all perfectly consistent with a flat-earth cosmology of the kind common in the ancient Mideast (and wholly inconsistent with twenty-first century knowledge) should not be at all remarkable. They, and their writings, were products of their age.
But even lacking a suitable single world, the sphericity of the earth could easily be conveyed by imagery. But all the imagery implies flatness instead. For instance in it's creation the earth is described as being "spread" out or "stamped" out or "pounded" out. It is never, for instance, described as being "gathered up". Likewise the heavens cover the earth like a tent. A tent covers a flat surface. Why not describe the heavens, for instance, to the rind of a fruit? Many such conveyances of the idea are possible, but none are used.