We know for granted that during an equinox, the Sun rises from the east and sets in the west. Such facts are undisputed and have been verified through centuries of observation.
The flat-Earth model, however, is unable to accommodate this simple fact. And thus, it is not hard to conclude that the flat-Earth model does not represent reality.
Let’s suppose we are in Congo-Brazzaville, Africa, close to the equator. When we are watching a sunset happening, we can agree that somewhere else in the world, there is a location where the Sun is directly overhead.
According to our map, the location in Ecuador, South America. From the so-called ‘flat-Earth map,’ we also know Ecuador is northwest from Congo-Brazzaville. However, according to observation, the Sun sets in the west, not in the northwest like ‘the flat-Earth map’ says.
Now the same thing but for a sunrise. During the time we see a sunrise in Congo-Brazzaville, there is a location on Earth that is having midday. The location is Riau Islands, Indonesia.
Using the so-called ‘flat-Earth map’, we know Riau Islands is northeast from Congo-Brazzaville. This expectation does not fit our observation, because the sun rises from the east, not from the northeast.
It is not hard to rule out the flat-Earth model from simple observation we can do ourselves every day.