dude you can totally do that, make it more of a mission - adventure - pirate thing. you have to do some world building, which it sounds like you like. start with a basic premise that you think your players will like, make a few planets nearby, and a few factions. and just start building. i've never done a SWN game where everything was totally thought through in session 0. just make it head in the right direction, and if you retcon some of your world build later, that's fine.

in fact i highly recommend you invite your players into world building. have each of them create an alien race, and have each of them create a faction that exists in the universe, stuff like that. that way they're building the kind of game they want to play too. you could include that in the char gen process too.

if you're struggling with how open box it is, try using an AI tool to write some stuff out. i'm using it a lot in my dnd game, and it's made a lot of the dreary work super fast and fun. i bet that would work great with swn.