Sacred Haven of Debauchery

I just don't see how to win here without resorting to war. Occupying 40% of the map is only possible by conquering other planets, as there's limited space. Maybe there are some diplomatic or federation mechanics, but for now, the simplest option seems to be gradually enslaving/committing genocide/subjugating other empires, hoping that the AI federation won't gang up on you. Although, this is exactly the kind of gameplay I envisioned when creating the race, so there's nothing to complain about.