It’s pretty simple to me how black holes grow....a star becomes so massive that it’s escape velocity becomes greater or equal to the speed of light....so everything that gets added to its gravity field makes it stronger? That’s what I’ve always assumed.
From what I understand it then reaches a singularity and then evaporates and disappears which I never understood. How can it evaporate if nothing can escape? What I would be interested in is if it could tear the fabric of spacetime.