If I was a really advanced civilization and the universe was nearing its end, I'd embark on a project of unparalleled scale that might wind up resembling a big bang with a spark of panspermia-precursor seasoned in.
Goosebumps thinking of how many universes could have played out before this one. Or alongside it.
Indeed, we know so little about the nature of things that it's really a bit premature to hold our current understanding as the final word over what will happen.
For one thing, a large fraction of possibilities involves simulations. In a simulation with successful traits, some constants and elementary particles might turn out to have been misunderstood later on...