Actually, a spherical Earth was proposed by Pythagoras as early as the 6th century BCE, and this was thoroughly established by independent Hellenistic scholars well into the time of Ptolemy (90-168 CE). This information was well known throughout the ancient world, spreading to India and the Middle East, and was a given to most sailors. This was also understood by most of the educated classes even into the Medieval Christian era of Europe.
It was only a segment of the Church that propagated the Flat Earth, or Disc Shaped Flat Earth theory, and it may have been the accepted view of uneducated land-lubbers.
However, just because the Hellenized cultures (including the Israelites of the time) of the Eastern Mediterranean believed
some things that were true, doesn't mean
everything they believed was true.
GB