https://youtu.be/w1r8dl4RqMw?si=BzEnCzbgv7oYNNwe
Only one engine was in reverse, and flaps were not down. The YT video also excerpts manuals and diagrams to good effect for a lay person who is not a pilot. Video of engine failing near airport may have been bird strike. They were in flight 4+ hours, so fuel should have been used to an extent, but don't they dump fuel when they are going to land in an emergency like this? The fireball was big, and they should have shut fuel pumps before flare up of reversing engines on runway.
The 1-foot-thick concrete wall for the atenna array seems to have caused it to impact hard enough to cause the most damage and fireball. The video points out there are lots of these with less robust structures at most airports.