So Many False Points
There’s no way the person who posted these points isn’t a troll. Firstly, the Earth is not flat, but it is big and great (subjectively speaking). Secondly, just because the Earth is 71% water doesn’t mean it will conform to its “natural” flat shape. Thirdly, satellites can travel upwards of 17,000 miles per hour, not 1,600 kilometers per second, which is not the speed of sound.
Fourthly, the water that’s “renewed” from the sky is from the water that evaporates on Earth, including our urine. Fifthly, we don’t have enough knowledge to talk about the sky dome point, but we’re absolutely certain the OP is completely wrong.