I think a better way to think about this is: what would humans do if they had a few crucial pieces of technology? Assume you have computers advanced enough to s

I think a better way to think about this is: what would humans do if they had a few crucial pieces of technology? Assume you have computers advanced enough to self-replicate and carry out some pre-programmed set of goals creatively (this is essentially required for Von Neumann probes to work, and doesn’t seem wildly out of the ballpark for even humans in a few hundred years.) My guess is that we would optimistically assume human survival and build a network capable of exploring the galaxy without us. Since lightspeed delays make real-time communication impossible, individual nodes would be programmed to replicate and explore, following a specific set of parameters. They would report their findings back to some central hub if they found anything interesting, which would probably be only rarely. No doubt for very surprising findings (eg advanced intelligent species) they’d have additional instructions to enter a holding pattern and observe until they received explicit commands. Which, as you point out, might never come. I can’t speak to what aliens might do. humans would absolutely build this system the moment they had the technology to do it. The fact that we might not survive to use it would be acknowledged and then we’d do it anyway. If anything we’d see it as a fitting memorial to our existence.