This is excellent! An appropriate response to the flat earth silliness.
For instance, what’s the tallest supposed mountain on Earth? Everest. Except it isn’t. The name is a giveaway; it’s clearly a morphing of “never rest”, because if you wanted to go to the biggest mountain you’d literally never rest, because it isn’t actually there. What about all those people who have climbed it, you say? Well, consider all the people who have died supposedly doing so. How do you die climbing something that isn’t there? You can’t. They were obviously killed to protect the conspiracy, whereas those who “survived” were willing to play ball.