I know that SF1e already have a similiar rule, but the rule wasn't as good as Pf2e Kingdom making rule. I think it's should be a solar system scale of managment, you could trade with The Empire or The Pact World, or other independent planets. You could make space improvement, discover news technology, and planetary combat, it's would still have some Kingmaker thing like structures, and commodity, but I would like it to be expand some more. New Structures but you can built improvement for that structures, so that the structure will be more effective yet remain the same size. New commodity type, like new fuel and energy, but also new way to use commodity to improve your structures and other civic thing.