I think the earth is not flat because if the earth is flat when you are around America you can see the statue of liberty from a distance. As the theory of seeing the end of the ship's screen from a distance gradually disappears.
Just as with Everest mountain, if we are on a plane that flies over Sri Lanka we can certainly see mount Everest.
So the earth is round not flat

And it doesn't work like that on the earth.

How do you explain video of a ships disappearing hull first into the horizon then being brought back into full view with a zoom lens?
I'm willing to admit when I've made a mistake and I'm wrong, you need to do the same.