lower floors did not give way.

what you find is the plane did not crash on the roof but into the side.
the damage it done on the floor it crashed into gave way. which then like a pile of cards destabilised each floor

|||||||||| 1
|||||||||| 2
|||||||||| 3
|||||||||| 4
|||||||||| 5
|||||||||| 6
|||||||||| 7

ascii display above shows 2 is the floor of the plane where 2 and 1 are showing smoke damage.
yes floor one did not collapse first. it was floor 2 that collapsed first. causing 1 to fall ontop and then the impact of that floor collapse then cascade effect caused 3,4,5,6,7 to fall

the stupid narrative that something like floor 7 (low) went first and shot out debris 500metres away has no evidence at all.