Terry was on my train of thought there. But if its not in time with wheel speed it can't be that. Not bump related. So that leaves the noise being movent of the mechanism related.
Try tightening the steering box bolts to chassis. This gives a very very slow frequency creak that actually sounds like a series of knocks.
"If" the noise can be replicated while stationary try standing outside the car, turn the wheel through the open window, then you can listen by the wing and feel components as they move. Or an assistant of course , will help.
If it doesn't do it stationary, that implies the suspension and steering needs to be loaded. So there may not be any point jacking the car on stands and moving the steering from underneath. But it may be worth a try.
Be careful of the pas pump but squeezing right full lock on and off can stress the system enough to give clues as well.