Yes I have. Because I am curious about how in 2018, people can still believe that the earth is flat. As someone who cares a lot about education and how we can equip people with the critical thinking and scientific literacy to be able to answer questions for themselves and not rely on just being told what is true and what is false.

I looked into the Suez Canal and you are absolutely right. It would have needed special planning if there existed significant curvature from the starting point in the north, down to the exit at the bottom. So that does suggest that there is no significant curvature there.

But is that necessarily an argument for a flat earth or against a round earth?

No.

Why? Because the Earth can also be round, but uneven. Here's the best model we have at the moment of the Earth based on the results provided from the GOCE satellite which measures gravity around the Earth. (The thinker the Earth is at a point, the stronger the gravity, so thus we can measure the shape)

And lo and behold: If you pause the video at 00:03 you can see that in the Northern part of Africa, the land is indeed "flat" within that limited plane.

Now I know this will not convince you that the Earth is round. But I hope it has at the very least demonstrated to you that examples such as these are not arguments against the earth being round or indeed in favor of the whole Earth being flat.