That's a good idea. Some quantum gravity models allow for a bounce, expanding to form a new spacetime region. The work is preliminary and some way needs to be found to derive testable predictions but there are QG models of collapse to black hole which do in fact bounce and initiate expansion.
Some authors (which can be looked up in arxiv) are Kevin Vandersloot, and Dah-wei Chiou.
Francesca Vidotto is working on something that might apply to this. Ashtekar has one or two recent papers that speculate along these lines. Leonardo Modesto is another who has studied the QG black hole. Sabine Hossenfelder too. Maybe I should get some links and try to organize the information.
Anyway it is remotely possible that a black hole collapse somewhere else can cause a new expanding tract of spacetime. We are, as you say, "free to imagine" this kind of thing. And some people actually study it. It's interesting and it hasn't been ruled out so far.