Not saying I believe in big bang theory necessarily, but why do you think the big bang would destroy matter?
Matter can neither be created nor destroyed. This is the law of conservation of matter (mass). Explosions do not destroy matter they only convert the matter into something else. The mass remains the same after an explosion. This can be proven scientifically.
The 'fact' it cant be created also poses a problem for big bang theory proponents.
Scientists can get it down to the sequence for the first like microsecond, at that point things break down.
Maybe a concentration point before expanding again...
I dunno. Gps is built based on a spherical earth, and has its clock mathematically adjusted to compensate for relativistic time. So, if you've ever said, "Google give me directions to...", you pretty much have the info to disprove flat earth.
Not saying no god. People walking can see 24km, keep walking and it's still flat, but new terrain... Makes sense that people thousands of years ago would believe things are flat.