With the other game you have been working on/talking about, I could see both converging to a game where you switch between dual roles of commanding a larger force and having to plan out paths/times to intercept and pick your battlefields, and then taking control of the action directly controlling your fighter in combat.
If you want to get real realistic/"expanse"-esque, you could have the fights take place not when they actually happen, but with delays based on how long it would take to transmit info back to home base, so in the commander's seat the player has to make decisions about other things before they know the outcome of a fight that is theoretically happening concurrently
A few of my threads of thought go in the direction of that too! I've been trying out Children of a Dead Earth some more and keep thinking an open world gameplay (rather than mission-by-mission campaign) would be really cool, although then making the AI seems like it will be a lot of work. And indeed whether you play as a fighter / fleet commander / base commander also changes the whole thing.