To get to the point, ships in the setting I'm working on still use a conventional, albeit very advanced, form of rocket propulsion.
However interstellar ships also use a sublight Alcubierre drive which can't efficiently be used for travel by itself. Rather the main use of the warp bubbles is to aid the ship in maneuvering, shielding and braking.
Instead of flipping and burning in the direction of their destination, ships usually reorient their warp bubbles, creating a gravitational gradient in the opposite direction.
However an inconsistency I foresee with this idea, is that if warp bubbles are strong enough to decelerate the ship, then logically wouldn't they also be powerful enough to be used as propulsion by themselves?
How would I handwave this problem?
How the technology works precisely, doesn't entirely matter. The only thing that I care about is that I don't end up breaking the setting with easy RKKVs or perpetual motion machines.