On one hand, there are flat-earthers who are not Christians. They've just seen the abundance of evidence supporting the claim, as well as flimsy ball-earth evidence, and was able to set ego aside and admit they were wrong.
On the other hand, there are just so many testimonies I've seen over the years of those who realized the earth was actually flat and God used that knowledge to reveal Himself and save them. I probably read at least several hundred of these by 2017. No telling how many there's been since then.
I do understand the desire to be part of the crowd can be strong. Like the old saying goes, nothing attracts a crowd like a crowd. I always think of the Logos Bible Software people, who came out with their diagram of how the earth is depicted in the OT, flat, pillars, dome, the whole thing, then those speaking for them, such as the late Dr. Michael Heiser, who actually stated that the Bible is most definitely a flat earth book, but that God was just telling the Jews what they could understand at the time because 'ball' was apparently too hard of a concept. He gave into to the lie of the day over the truth of scriptures.