Genesis 1 and the Shape of the Earth

I recently saw an argument that since the earth was created before the sun in Genesis 1, the earth must be flat. How does someone who thinks like that even have meaningful conversations with other people? It's like saying, "My son was born before my daughter, therefore my daughter is a tree." The one has nothing whatsoever to do with the other.

Maybe if they had argued that Genesis 1:2 says "the earth was without form", therefore the earth can't be a sphere, it would at least have some kind of internal logic. However, just like all human language, no matter how technical and precise, the Hebrew of Genesis 1 uses idioms and figurative language, which is then translated into another language (e.g. English) that uses idioms and figurative language.

The earth was without form (תהו) and void (בהו), and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters.
Genesis 1:2 ESV

"Without form" is the Hebrew word tohu, which can mean formless, but can also mean unorganized, pointless, or useless. It rarely refers to anything's actual shape. "Void" is the word bohu (notice the rhyming?), which means empty, pretty much exactly what void would mean in the 17th century English of the KJV. It's not a technical term referring to the vacuum of space, but empty like the Sahara desert is void of trees.

The picture that Genesis 1 draws of the earth immediately after its creation is of a muddy place without clear delineation between land and sea, dark, useless, and lifeless. You, the reader, have to read into the text your own idea of how the universe works before you can find even a hint of the earth's shape.