If our earth is supposedly 71% water then it can't possibly be round, oh and don't forget the magic of gravity, or should I say density and buoyancy..
Here's an interesting fact about mass: It attracts things to it. The force of attraction (gravity) between two objects depends on their mass and the distance between them. Simply said, gravity will pull toward the center of mass of the objects. To find the center of mass, you have to examine the object.
A SPHERE'S CENTER OF MASS
On a sphere's surface, gravity will pull you toward the sphere's center of mass: straight down.
Consider a sphere. Since a sphere has a consistent shape, no matter where on it you stand, you have exactly the same amount of sphere under you. (Imagine an ant walking around on a crystal ball. From the insect's point of view, the only indication of movement would be the fact the ant is moving its feet—the shape of the surface would not change at all.) A sphere's center of mass is in the center of the sphere, which means gravity will pull anything on the surface of the sphere straight down toward the center of the sphere. This will occur no matter where on the surface the object is located.
Consider a flat plane. The center of mass of a flat plane is in its center, so the force of gravity will pull anything on the surface toward the middle of the plane. That means that if you stand on the edge of the plane, gravity will be pulling you sideways toward the plane's middle, not straight down like you usually experience when you stand on Earth.
A PLANE'S CENTER OF MASS
A plane's center of mass is in its middle—which means that gravity should pull objects toward the center of the plane.
https://www.popsci.com/10-ways-you-can-prove-earth-is-round#page-15
Oh and 71% of the earth's surface is water, but only 0.05%(0.0005/1) of it's mass.