Wtf? A quote saying you can reach the end of earth and that earth has 4 corners is not a proof of it being flat?
No, it's not proof of the earth being flat.
The earth is round, as it says in the Bible.
I'm surprised that you think there is proof of the earth being flat.
The earth is not infinite, and therefore has ends. I'm sorry if you think the earth is infinite, but it's not.