I'm only going to be second guessing here. It was a terribly sad day for all involved.

From the videos I see, it appears the horizontal stabilizer is gone. Maybe I just couldn't see it though. But if so, it might indicate overstress from attempting to arrest a hard descent & too many Gs pulling back on the elevator. If the horizontal stab was gone, then the show was over at that point. 60 degree bank made no difference, it was uncontrollable and IF the horizontal left the plane, there were no mre G loads to be had. The wings were still on it appeared.. I would assume in that kind of a descent, she was at idle power. But again, it made no difference.

My experiences were in smaller planes, but it was always best to just hold a level flight attitde and just ride in the up/down drafts. The outside air temp she gave was unbelievably cold, and she reported rain, so my guess was the rain might've been heavy hail. If the hail was heavy enough, she could've had a double flame-out. With all the other problems, that wouldn't be good.....obviously.

Perhaps her weather radar was malfunctioning, but normally one would attempt to circumnavigate those huge buildups. It doesn't appear it was that wide of a cell. Maybe 20 miles one way or another would've made a difference.

Again, I could be 100% wrong about my presumptions.