AF 477 stall
Another thing that most folks haven't spotted is this. Once they developed a deep stall with forward speed below 100 and vertical speed in excess of 100kts the angle of attack would have been greater than 45 degrees. That means that to unstall they would have had to lower the nose from what they had (15 deg nose up) to say 50 deg nose down to stand any chance of unstalling. That is a pitch change of 60 degrees - in the dark and with them in a state of panic not knowing what was going on. It was all over by the time they reached 25000 ft. Nothing after that was going to work. So, when you get into airspeed unreliable territory, fix onto ground speed and you will stay safe.
The rules are simple
Maintain pitch and power that exists and maintain the same ground speed. All is well.