Yo, so there are actually countless Hive we don't know much about with more than enough power to have their own "realm", similar to Daedric Princes in Elder Scrolls lore having realms dotting Oblivion. There is MUCH we don't know, but rest assured; there are definitely Hive somewhere as powerful as the strongest foes we have faced so far. I imagine the Hive overrealm (the one that overarches all other realms) has a sort of way of life to it, and more powerful Hive sects exist solely to care about their home. They could even have forsaken Hive who prefer to try and take planets for their own, instead favoring the ruling of their one true home.