>>859I'd say the head curves in a bit too sharply/soon towards the back, making it look as if squashed in from the sides.
The top of the head is somewhat flat, makes the head look box-like in the side pic.
The face is basically fine but doesn't match the size/shape of the head.
Comparing the 3D to the reference, Beethoven's head has more volume (the head itself, ignoring the hair).
Rounding/bulking out the head a bit on the sides & top should help.
The hair looks ok from the front, but off from the side. 'Directionless' for the lack of a better word?