I have a very hard time understand a prolonged 30 degree dive until impact. I only saw that kinda pitch angle when delivering ordnance or performing aerobatics.
It happened to the FlyDubai Boeing 737 too. Steep dive after a go-around not helped by the pilot holding full forward stab trim all the way down.
See:
https://en.wikipedia.org/wiki/Flydubai_Flight_981