okay, say the earth is flat.
That means, according to ever flat earth map I have ever seen, that South America, Africa and Australia are all opposed by roughly 120 degrees. The three continents face away from one another. Yet, at any given time of night, People on the same latitude in Australia, Africa and South America see the same night sky, albeit at different times. They see it all revolving around the same point in time lapse photography.
Now, what geometrical object do you have where you can have three people, each opposed to the other by 120 degrees face outward FROM one another and see the same point? Only one:
A sphere rotating on its axis. Or being rotated about, given geocentrism.
If a flat earther can clearly and unambiguously explain how three continents, each opposed to the other, can have people standing on a common plane, each facing AWAY from the others and all observe a common POINT I will become a flat earther.