And with all that analyzing, are you any closer to figuring out just what the heck is going on?
Oh my, I could write a lot about it, but I'll try a "short" version without quotes, references etc. first:
The main setup seems to be that just like a big bang started the existence of our universe, there happened another one ca. ten years before the game begins. It was calles the Death Stranding by the survivors and it shook up not only the physical world but also the rules of physics.
Like many popular science fiction stories nowadays there are references to quantum stuff and other dimensions existing. The main idea is, that different dimensions "collapsed into each other". After the Death Stranding – it seems – it's clear that "dying" was actually being transported into another dimension (which different religions refer to as Hell, Hades etc.) and these dimensions now exist within each other.
Therefore, your character can't really die, but for some reason, every death causes an explosion, which is called "void out" in the trailers (and these explosions seem to cause huge craters, which can be seen in the trailers). So when you die, you wake up in an alternate dimension (the war zones in the trailers, like WW1, WW2 and Vietnam) and have to fight your way out (somehow returning to the original world).
The goal seems to be to connect the cities of the former USA, which remained an apocalyptic landscape after the Death Stranding. So some places seem livable, the cities, but they are disconnected by the void-out craters. That's why the main character carries supplies, people, ladders and ropes – and builds "Bridges" between the cities, which actually is the name of the (government?) institution, he's working for.
So, that's a short version. Did it help?