The Bible never says the earth is flat. The closest argument one could say is that the Bible says "the ends of the earth" but usually when this is said, it's referring to an instruction to preach or spread information across the whole Earth
It also could be a translation with double meanings (as that often happens with different languages). For example, some translations opt to say "remotest parts of the earth" instead of "ends of earth"
Also, I've seen many pro-flat earth videos, and many of them begin with "what if" scenarios, take the "what if" as fact, argue from there, and reach a conclusion. They also often just throw out any opposing arguments that challenge their pov.
Also the flat earth model makes no sense bc of the moon's reflection of the sun, which is always blocked by earth. If Earth was flat, we'd have very different moon phases.
And there's no way the Earth's gravity comes from rocketing upwards like Sokovia in Avengers 2. That would mean everything around us would be doing the same thing despite not being flat. The moon, sun, planets, Milky Way, other galaxies, etc.
Here's the craziest part. The flat earth community will call every picture of space a hoax. This barely makes any sense bc CGI was trash in the 60s and NASA would never have been able to fool the globe into believing a staged moon landing back then; plus, in order for such a conspiracy to even work, the Space Race would have been staged, and since the Space Race was a direct result of the tensions leading to the Cold War [the USSR vs USA's political opinions spreading throughout the world], this would make the 1950s contrast between communism and capitalism completely staged, which is completely impossible. If we faked the moon landing, the USSR would've gone out of their way to prove it. Bc of political tensions in the 50s, there is absolutely no way we faked the moon landing.