1) Gravity - I have yet to see any compelling argument that explains gravity without using Newton's laws of Physics.
2) Stars and Moon - In the northern hemisphere, the moon appears different than it does in the southern hemisphere. Also there are different stars in the sky.
3) Lunar Eclipse - During a lunar eclipse, you can see the shadow of the Earth on the moon.
4) Day/Night - There is no way that a flat earth model can explain sufficiently how night and day work using a circular light delusion.
5) You cannot see the the Sierra Nevada Mountains from Las Vegas. It is the driest place in the world and if it was flat, they should be easily seen with a telescope.
6) Satellites - We depend on them daily to get TV signal, GPS services, and communications to remote locations around the world.
7) Felix Baumgartner. When he jumps you can see the curvature of the earth easily. His story cannot be realistically denied.
No one has been to the edge of the flat earth. Not even Steve-O, who is probably the craziest person on the planet.
9) U2 Spy Plane pilots can see the curve of the earth. I knew an air force pilot that flew the SR71 and asked him if he could see it, and he said yes. It was like he was in space.
10) 536 Astronauts have been to space. Also the columbia space mission in 2003 is a well documented mission to space that ended in tragedy. It was videoed until their last minutes they were alive on Feb 1st 2003.
11) There is no world map that does not have distortion. Only a globe can be reliably used to measure distances to anywhere in the world.
12) Many explorers traversed across Antarctica bearing the bitter cold. The latest trip took 53 days and was well documented.
https://www.nationalgeographic.com/adventure/2018/12/explorer-completes-historic-antarctic-trek/ I am sure I could go on, but I think that basically until I see a flat earth map that shows an Antarctica that can be traversed, that shows a 50% light/darkness ratio, and no distortion of the land masses, I am not buying flat earth. These things are all easily able to be shown with a Globe and from my experience, usually the simplest solutions are the best solutions.