>But I never hear anyone address how time becomes spacelike.
Take a region of space, let everything that could exist absorb heat. Take the same region of space, and emit enough heat to create a voltage in anything that could look at it.
Fall of the cliff of all things nature that want heat. Don't just have a parachute to slow your fall to non-existence, but a jetpack to absorb some heat of your own. Absorbing heat, you can now emit heat. Something asks "anything exists here?" you now have an answer.
Nature has no internal mind, no distinction between time and space. Heat transfers through mating conductive surfaces, flowing convective mediums, or the nothingness of electromagnetic radiation, like sunlight going through the vacuum of space to warm the Earth. Special relativity provides a medium. It's easier to slow down the ticks of your own clock, move, and speed up your own clock again than it is to just move.
At best, nature sees the photoelectric effect, brightness converting to internal voltage, which we see as "clock speed locality" and volumes of voltages. At worst, nature doesn't even make that distinction. It's easier still to have wiggle rooms in your answer. I slow down my clock when you say I'm going to move. I move when you say I'm going to slow down my clock. Looking back, both are true, whatever is in my advantage, because I hold the cards, and I make that potential a medium in of itself.
The way I reason about black holes is that they tell more about what's around it than what's there. Everything that could exist is in agreement that we all dump heat there. I'm really interested in seeing if we can point a telescope at a black hole, and cause something elsewhere. Or point a telescope at everything, and see if the black hole does something, like pair production.
Gravity and massless photons are such loaded terms promoting mysticism. Newton's idea of gravity, a cannon on top of a mountain shooting a ball that falls down as equally as it transverses lengths is a good place to start. No absolute position, everything is relative motion, and sum up yourself to all relative motion you are accelerating. Then move onto fields and Maxwell. Ticking clocks slow down and speed up for advantage. Before you get brighter, you need to charge up some internal energy. That's Planck, and Einstein brought the photon by relating that to relative time creating a voltage.