I think one major difference is that flat earth-ism requires blatant worldwide conspiracies whereas young earth-ism could be compatible with mere worldwide inco

I think one major difference is that flat earth-ism requires blatant worldwide conspiracies whereas young earth-ism could be compatible with mere worldwide incompetence. It's not so hard to accidentally screw up radiocarbon dating of a sample. And it's not unheard of for a whole field of study to royally screw up (e.g. the replication crisis in psychology). But it's very hard to accidentally screw up "this weather satellite takes a picture of the earth every hour and it clearly shows a sphere". And the flight paths of planes. And and and and ...