A few random observations from the video...
It's clear all was not well at the propulsion end of the craft, and it got worse as time went on.
It looks to me like the ship might have initiated its own self-destruct from the propulsion end a few seconds before the signal was sent from the ground?
It also seems to me that someone forgot to read the part of the manual that says when the boosters are firing and the nose of the craft points in the direction of Earth, you press the destruct button *now* and don't wait a few tens of seconds for the ship to change its mind and head back toward space.
I came here to post the same video (for those who, like me, have issues with the yout.be versions:
https://www.youtube.com/watch?v=NCYSVmSPM7E)
It is crazy all the debris and rocks (some of them car-sized) and even mechanical parts that are shot at high speed in every direction. Although the dust clouds obscure the area close to the ship, it is clear that many of the projectiles must have hit the engines and other parts.
With that in mind, it is not surprising that 6 to 8 engines failed, and it is not surprising that "all was not well at the propulsion end of the craft".
You can see engines that are off already as soon as they become visible, others sputtering, others shutting down later, leaks, flares, abnormal flames.
Also you can see the paddle grids of the thruster deployed, I would think that is not normal during launch.
The ship survived all that, plus tumbling several turns, plus going supersonic with 90 degrees of AoA, PLUS THE FLIGHT TERMINATION SYSTEM which WAS activated and the explosive charges DID punch holes in the fuel and oxidizer tanks , but the rocket resisted to die. Apparently, only after several tanks vented all their contents and their internal pressure went to zero, which reduces a lot the structural integrity, the structure of the ship collapsed.
This thing should have exploded on the launchpad. That it survived all that is absolutely astonishing.