It sounds like there was no radio contact reporting a problem. So whatever happened happened fast and required the crews full attention all the way to the end. That’s the only speculation I’ll offer...
I think that’s the clue - no distress calls, no radio contact. There one minute, gone the next. Something so sudden that the plane was gone before anyone could make any contact.
How sad.
Shades of Air France 447 a few years back. At the time I think we were almost all thinking about a terrorist bomb, and in the end it wound up being a frozen pitot tube compounded by pilot error.
}:-)4