I’ve seen the videos and no the Earth is not flat.
The world looks flat but you can also see it is not with your own eyes. You don’t need a balloon. I once drove across Lake Pontchartrain south toward New Orleans. It’s a very long bridge and a very big bay of water. For 8 miles in the middle, as you drive along in your car, you will see the land behind you dip below the horizon and you will see nothing but water in all directions. As you continue to drive, you will see the tall buildings of New Orleans rise up magically out of the water, because they are over edge of the earth’s curvature.