[EA]

We landed on the Moon. Frame-by-frame analysis of the dust coming off the Lunar Rover at the speed and trajectory shown on video from the Moon proves the Rover was in 1/6th the gravity of Earth [1]. There was no way for that 1/6th gravity to be faked on Earth in 1971. Incidentally, probes recently sent to the Moon show where the Lunar Rover made paths in the dusty surface of the Moon, and those paths align with the original video from the early 1970s.

Flat Earth only has a handful of anecdotal short-range observations of some flat areas of Earth taken from a perspective near ground level. Relative to the size of the Earth, those short-distance observations are dominated by the margins of error in the observation. All of those sight lines are accounted for in LIDAR scans of the Earth as well as the WGS84 model.

For less than $1,000 you can send a high-altitude balloon up to see the slight curvature of the Earth. For a few thousand dollars, you can circumnavigate the Earth in an airplane along a common latitude. For tens of thousands of dollars you can go to Antarctica and see the 24-hour Sun from November to January. Or you could just have all your friends from around the globe point to the Sun and measure that angle. With basic trigonometry, you can see the Sun is about 92 million miles away.

[1] Hsu & Horányi (2012), University of Colorado Boulder - "Ballistic motion of dust particles in the Lunar Roving Vehicle dust trails," American Journal of Physics: https://ui.adsabs.harvard.edu/abs/2012AmJPh..80..452H/abstra...