If you open your eyes and watch the real-world sunset, . . .
Exactly!
If you open your eyes and watch the real-world sunset - and - you are keenly aware of what you are looking at - you will notice that the sun is "followed" by a pattern of light that
does not match what you would expect to see in a Ball Earth scenario.
According to the Ball Earth model, the transition from [direct] sunlight to [complete] dark
should occur very rapidly (about 2 minutes or so) and
equally along the entire horizon (because light from the sun is considered to be parallel to all [direct] points of the earth) - and would be
the same for each and every place on earth, from pole to pole - as the terminator line "passed over/through" that place.
However, that is not what we see.
Moreover, the time factors are different in the North from the South. The light-to-dark times vary from place to place and season to season. This is not what the Ball Earth model suggests.
Also - the North region within the Arctic Circle should experience
the identical same characteristics - six months removed - as the South region within the Antarctic Circle.
However, that is not what we see.
What we see is a pattern of light that "follows" the sun beyond/over the horizon in a way that is "wrapped around" the sun and "shrinks" with the sun as it moves beyond sight. (Which is
not as it would appear if a terminator line were passing by/over/through.)
And, the time it takes to do so varies from place to place and season to season - and, in most cases/places/seasons, takes
significantly more time than the Ball Earth model allows for.