I did a sim in january with a loss of all flight controls. We landed back onto 31L at JFK with no damage using back up only (A340-600). Just to prove it wasn’t a fluke the sim was reset and we did it again, also without damage. Since the Sioux City incident we tend to look into things like this to a greater degree. For example, prior to that incident Airbus operators used to look at flying in back up mode was just something you would have to do until you could reset enough systems to regain conventional control however nowadays we see flight in back up through to its conclusion.

The A340-600 has the great advantage of a back-up yaw damper (independent). Without it things may become tricky.
With differential thrust one can change direction (very gently) and with overall thrust one can control pitch.
The A380 was built with experience in those accidents in mind. Minimum flight controls often suffice when crew is experienced and conditions are OK. You can land an Airbus 320 in backup mode (just trim and rudder).