Hey there, welcome to the forum.
Most Flat Earthers are primarily concerned with the shape of the known Earth - that is, the continents we know and have explored - rather than the outside. Views about what exactly lies beyond the ice wall/firmament are divided. Personally, I find the shape presented in this video to be hard to believe, but it would be interesting to see its proponents present a more complete model and make their case to the wider FE community