the aircraft hit the gorund going almost vertically down with hardly any forward speed.
Which is most probably just an optical illusion due to the viewing angle and the distorted view through the windscreen. You can see the aircraft getting bigger quite rapidly, so although it seems to stand almost still, it was in fact moving fast. During impact you can see debris moving forward rapidly trailing burning fuel. Compared to the size of the fuselage they travel at least one fuselage length in a second, so some 100+ kt. Without forward speed the roll rate to level the wings would not have been possible either.