All Boeings and Airbus are entirely reliant with no fallback options
Wrong re Boeing - dont know re Airbus.
Thru the 777, BA has always had cable backups, direct to a minimum number of flight controls and trim tabs. Simply push/pull hard enough to override autopilot- safety limits, etc. 707 and 747 aircraft have been saved by that concept- the pilot always has the final word despite many bells and lights and buzzers, and pull up warnings.
read about the Gimli glider for but one example ( 767) , a China 747 over pacific for anouther, and early 707 over atlantic- wings were bent- but remained in service