I would suspect that the real draw to working with Starfleet for non-federation personnel isn’t any concept of wages, but a comprehensive benefits package. Presumably Starfleet membership confers some level of personal federation membership, possibly for both you and your immediate family, which may mean that you get to move your loved ones to a mostly-utopic federation world.
The problem with Watch Dogs Legion is that all of the player characters are all procedurally generated, so while there’s plenty of plot, it’s pretty threadbare as a story.