My bad. Is the formal organisational term just “fleet” then, and other fleet-sized but not org-charted collections of ships are just unusually large task forces?
I note in the glimpses of future history we have had, that the Republic never does try and tip over the game board before it loses and fragments quasi-peacefully. So, Ragnarok would be from some other frontier or something unpleasant boiling up from the non-plexus stars in the Worlds?