I think part of this story (yet to unfold) is the altitude/timing that was given to the aircrew. Maybe if they’d had another 5,000 feet, it would have made a difference in recover time.
My hypothesis is neither one of them knew much about flying the aircraft manually, and had no idea the trim had been adjusted to put the nose down.
A pilot would have to be really bad not to notice the trim moving automatically. The wheels are large, right next to the arms of both pilots, and make noise when they turn.