A lot of the problems stem from a "perfect storm" of small things,
I have read the reports and followed this (I’m in Building Control)
the separate compartments were compromised by damaged doors on corridors, snd holes in the floor/ceiling left unsealed when they installed gas a while back, so the stay put advice wouldn’t work like it should,
the building was clad in a material that was only approved to be used up to a few story’s,(but £500k cheaper) the windows were fitted in the outer cladding, which fell off, the gap behind the cladding should have had fire barriers every floor to stop spread of flames.
The lack of sprinklers was apparently because they didn’t expect the system to last long due to vandalism.
One fault after another, plus the fact no one knew exactly who was actually living there due to sub letting etc.