4500’ TORA is not much.
That take-off roll looked sluggish to me also. It just appeared it was being held back with weights or something.
Is the application of full/calculated take-off thrust on the brakes a common take-off procedure for these jets? It makes me think the crew felt it was going to be tight from the off.
edited to add; as the aircraft passes abeam the videographer standing on the ramp, you can see the elevators deflect upwards and then hear the engines move to idle. Appears the trim/nose heavy issue mentioned by others above could play a part.