Note that The Bible officially declares several times the flatness of the Earth (Matthew 4:8, etc.) and that the Sun, Moon, etc. all go around it.
The original Flat Earth Society was founded on this. In later years, it got a lot of “members” who signed up for the fun of having the membership certificate for their wall. It went moribund, got revived thanx to the Internet, etc. Who knows what percentage believe what now.
It is incredibly easy to show that it can’t be. E.g. make a phone call to someone on the opposite side of the globe and compare day/night.
But these … people … have thought of that. They have an incredible “system” for explaining all the oddities of the position of the Sun wrt a flat Earth. Their concept of Optics is strange and then some.
Sometimes someone will show up here pointing out some oooolld, badly done “experiment” that disproves the curvature of the Earth. It’s hopeless arguing with these folk.
Just think of how weird GPS would be for a flat Earth, alone.