The flat Earth myth is so widespread there is no hope. I hear pastors regularly make reference to it and when I ask Christian church people everyone accepts the myths. No wonder because they are still in textbooks and repeated as common sense fact everywhere. Drives me crazy but then this current generation is as ignorant as any other in history about history and reality.
FWIW, I remember from my days back in school in the 60’s our history books having PICTURES of the flat earth with waters falling off the edge and with (iirc) some kind of dragons or something off the edge waiting to further doom those who went off the edge of the earth.
We also had texts that taught a new ice age was coming.
And texts that clearly stated that life began in an ancient time when lightning struck a protein soup type body of water and the first cell began, and from it all other cells evolved.
The evolutionists deny such things ever were taught, but I distinctly remember it.
I also remember being taught that one of the fears of Columbus time was that they’d sail right off the edge of the earth.