"don't we need to understand the /actual/ creation of space and matter in totality"
Well, there are some hypotheses on what caused the Big Bang in the first place (and as a result, all of space, time & matter) but they are currently relegated to thought experiments. We just don't have the technology yet to test them. There might be some things that could show up in more detailed observations of the cosmic microwave background, things which if found would be suggestive, but the evidence still wouldn't be conclusive.
You can google "what came before the big bang" to read up on those hypotheses. Keep in mind that they are thought experiments. Pop-scientists will often talk about those hypotheses like they're fact, but the truth is there's still a long way to go.
Well, there are some hypotheses on what caused the Big Bang in the first place (and as a result, all of space, time & matter) but they are currently relegated to thought experiments. We just don't have the technology yet to test them. There might be some things that could show up in more detailed observations of the cosmic microwave background, things which if found would be suggestive, but the evidence still wouldn't be conclusive.
You can google "what came before the big bang" to read up on those hypotheses. Keep in mind that they are thought experiments. Pop-scientists will often talk about those hypotheses like they're fact, but the truth is there's still a long way to go.