I think it was either a Miniminuteman or a Folding Ideas video that showed what some flatties proposed: the Sun moves in a wacky repeating spiral pattern above the surface. It’s closer to the Arctic during summer and to the Antarctic during winter. Obviously that doesn’t conform to any physical laws, observed phenomena, or reasonable ideas that a person of ordinary intelligence might come up with… but that simply reinforces their belief that everything else is a lie and they figured out the real truth.