Another visualization: if you had an Earth mass black hole with a solid shell surrounding it at the same radius as the Earth’s surface is from its core, gravity atop that shell would be 1g. The actual black hole would be about the size of a marble.

If you got close to it you would of course be subject to insane gravity and be “spaghettified” etc. All the mass would be in that marble. But at a distance it would be the same.

Compared to that object the Earth is mostly empty space. Ordinary matter is not that dense.

Black holes are totally fascinating. They are in some ways the most extreme objects that can possibly exist. If we could study one we could learn a lot.