White holes and wormholes are probably real. Here's why.

Non-spinning and non-charged blackholes are called Schwarzschild or static black hole is a simple beast. You have a event horizon, a mass, and a slightly strange area near the event horizon where orbits are unstable, I believe within 1.5 times the event horizon distance. Spinning blackholes (Kerr) of are quite complicated in comparison. They have an outer ergosphere, inner ergosphere, outer event horizon, and an inner event horizon. Also the singularity is no longer a point, but a ring. A quote from the Ring_singularity link below: An observer crossing the event horizon of a non-rotating and uncharged black hole (a Schwarzschild black hole) cannot avoid the central singularity This is not necessarily true with a Kerr black hole. An observer falling into a Kerr black hole may be able to avoid the central singularity by making clever use of the inner event horizon associated with this class of black hole. This is also explained in the Veritasium video at 1610 seconds: [this video] More info at: [link] [link] [link]

I would think the most difficult part is figuring out if it's even possible to tweak the universe to be more favorable to life than it already is. Maybe it is possible to form more stars, but the same tweak would also form too many sterilizing supernovae? In any case, I'm inclined to believe that other universes exist simply due to how easy they are to find by extending a penrose diagram [1], and that the "natural selection" of "universe reproduction" eventually leads to a universe with parameters that enable life and consciousness. [2] Unfortunately, this method still can't tell us how often alternate universes are capable of life or how much the parameters can vary. [1] [this video] [2] [link]