I remember watching a documentary a few years ago on Netflix about Flat Earth called "Behind the Curve". Every experiment the flat earthers tried, failed. For example, they bought an expensive gyroscope ($20k) to try to disprove the earth is spinning 15° every hour (because if the earth is flat it doesn't spin, I guess?). Their first test failed and proved the earth IS spinning 15° every hour. They couldn't have that, so they said it wasn't the earth spinning, but "the heavens" and put the gyroscope in a Zero Gauss Chamber. But it didn't make a difference. The gyroscope still gave a reading of that pesky 15°.
They had several other experiments to prove their theory was correct but in the end, they disproved all of them. lol. But, of course, they refused to admit it so they're still searching for their proof.
I wish one of those rich flat earthers would take a team to Antarctica and show the world what's out there. Wouldn't that be a relatively easy thing to accomplish? But I imagine they don't do it because they know, deep down, that their theory would be utterly crushed.