Mu.

This answer is based on watching a bunch of PBS Spacetime videos. I am not remotely an astrophysicist.

When you delve into black holes, the concept of "sphere" eventually becomes ambiguous. A black hole is an infinitely-dense region of spacetime, called a singularity, which has only three properties: mass, angular momentum, and electric charge.

What most people think of as a black hole is a region bounded by the event horizon. The event horizon isn't an actual thing, it's a mathematically-defined radius around the singularity. You would no more notice crossing the event horizon than you would crossing the boundary of a timezone on Earth. If the black hole's angular momentum is 0, then the event horizon forms a sphere, because all points on the event horizon are by definition the same distance from the singularity.

But things get weird when the black hole is rotating. Because of some stuff I don't quite understand, rotation causes the singularity to turn into a ring rather than a point, so you could theoretically drive a spaceship through the hole in the middle (you could not actually do this because by the time you get there your spaceship will have been vaporised by the accretion disk and torn apart by gravity). In this case, the event horizon forms a sphere that is squashed along its axis of rotation, kind of like Earth.

But black holes are weirder still! Scientists say that they break physics, but it's even more fundamental than that. A bit below the event horizon, time and space themselves swap, so that the singularity changes from a point of irresistible attraction to an inevitable point in the future. The maths suggests that, if you were to hit the singularity, you(re atoms) would emerge in a universe with time instead of space and space instead of time.

It's bizarre is what I'm saying.