You rang?
I don't want to give spoilers about Ko, but the bigger things have already been mentioned, and Ko's IC motivation generally lines up with yours. "A Republic able to stand on its own, as an equal, is best for all, including the State." The less of a reliance on the Federation, the more likely the Republic and the State can warm up to each other on equal terms - at least in her head. Plus, should a Reclaiming ever be aimed at the State, there's the experience of having already been fighting them to help against that.
It's also comfortable from a social perspective, because the family, clan, tribe, nation of the Matari can easily mirror the family, corporation (or still clan, in her case), mega, nation of the Caldari. It's nicely familiar for her to work in that environment and social structure.
Sprinkle in her family's version of The Way, and the little Stargazer says, "WTF forced 'enlightenment'? What is this? I do not even..." So, off we go to help and to hope.
Of course, ask her IC why she's part of a pro-Matari corp, and you'll get told, "I was hired." Most seem satisfied with that answer and don't ask further.
FW made the mental gymnastics to reconcile the two sides a bit more troublesome, but it's not too hard. From IC experience, it's less the Caldari who create any friction than Matari your character publicly disagrees with or Federales trying to cast your character in a suspicious light. But, it can still become a rocky road very quickly, and that's when it gets fun.