Even those ancients who MAY have believed in a flat Earth believed that the Sun went under the rim of the world.
The great irony here is that modern flatters continually appeal to the “common sense” evidence of the senses - except when it comes to the Sun rising and setting. THEN they invoke terms like optical illusion and hocus pocus mechanisms.
Just like with the gravitational force. They laugh it off as magic, despite the universal applicability of its equations to both local and celestial mechanics - but then they invoke words like “pressure” and “density” without being able to account for why their “pressure” has a downward vector in the absence of an external force field (the reason something above you exerts a pressure upon you, whether is that it’s being PULLED IN a DIRECTION) or why objects still fall INSIDE VACUUMS (don’t even bother, you will never get an answer). Of course they have to deny the existence of a gravitational central force because it is incompatible with a finite flat
disk, not to mention a cylinder which would pull you toward its center.
In the case of the really dumb ones it’s “because down is down, duh” - yes, clearly it’s gravitati theory that is “absurd” (as if things attracting one another based upon their mass were any weirder than the electromagnetic force - we can have magnetism but we can’t have gravity, no sir, that gravitational stuff is a priori absurd because ... because ... because modern materialists HATE the notion of action-at-a-distance as it interferes with their only conceivable notion of causation, that of Democritan billiard balls bumping into one another)