… And furthermore, it wouldn’t require “30,000 feet”, as @Aupmanyav stated.If the sea level rose 30,000 feet it wouldn't crush everything.
In the bible it says the waters rose from the deep as well as rained down, which wouldn't crush every thing.
Psalms 104 explains that the “Waters” made the ‘mountains rise & valleys fall.’ (If one is going to ask questions about the Biblical Flood, then the Bible should be consulted to explain some aspects of the Flood, where it discusses it; don’t you think?)
So Psalms 104, when you reason on it, is telling us the Earth was smoother, topographically speaking, before the Deluge.
It makes sense; if waters spewed out from “vast” springs, the land directly above would have to fill that vacuum, i.e., sink.
But mountains have been found to have roots (look it up, it’s interesting); no doubt those roots help to stabilize the mountains. So by the surface sinking / deflating, many of the highest mountain ranges were formed.
And when you study the details of many of the mountain ranges (not all), they do appear youthful, geologically sealing, with crisp well-defined features despite the intense weathering and erosion they endure.
So…30,000 feet would not be needed.
Im not saying it was ever this smooth, but if the Earth were smoothed out like a cue ball, the volume of water we have now would be sufficient to cover the land 2 1/2 miles deep.
And within the mantle, more water is being discovered. (Google ringwoodite.)
Just sayin’.
So long, my cousin.