Look up to the sky. Even with your naked eye you can see the moon is not a disk but a sphere. But you dont trust your eyes, fine, get a telescope and look at it. Yeah, its not a disk, Its a sphere. Now ask yourself if it makes sense that there is a sphere in the sky, but we are flat?

If you are SO skeptical, then here is a better idea than looking at UN map or freemason symbols. Buy yourself a very powerful telescope, get to a nice harbor town, and watch the ships coming in and out.

Okay, you dont like harbor towns and telescopes. Fine, go with a buddy into a open field. Get to poles, fix a laser to the top of the first one, shooting the light horizontallu. Put a receiver at the top of the other. Move the poles further and further and see how far before the receiver stops receiving. Repeat with the lasers at different heights. BONUS - calculate the earth's curvature using this experiment.

There are UMPTEEN ways to convince yourself what the shape of the earth is. No one in their right mind believes earth is round because "Nasa said so" or "Freemasons said so".