Barely related but you’ve spurred a thought into mind:

Would a hive mind or other gestalt consciousness even have the drive to reach the stars outside of circumstances involving potential extinction? I feel as though a GC who has reached the galactic stage would perhaps (almost necessarily) be a fanatic assimilator that had assimilated a race who has a drive to be spacefaring.

My theory, a Terran like imperialist force hailing from a dead world attempts to colonize a habitable planet, only for the colonial force to become assimilated into a fungoid hivemind who has never considered life on other worlds, nor that their world could potentially not be eternal. This spurs action in the hivemind, a drive to expand to other worlds to secure their eternium, and with this newfound difference in thought a drive to assimilate more and more species to see just how different thinking can be