Credentials:
30 years plus on Boeings, 20 years plus as wide body Captain.
Not being one to speculate but maybe they lost an engine and instead of drifting down stalled the aircraft, then put in the wrong rudder or tried to use aileron to recover the dropped wing then ended up inverted in an energy and attitude state that was beyond their capability to recover from.
But I guess we will only know when the CCP release their transparent report into the incident.
My condolences to all on board.