Input.multiTouchEnabled not working

i use Input.multiTouchEnabled = false but
public void OnPointerDown(PointerEventData eventData)
{

}

still input multi touch

i use new input system

Indeed use the new input system, that works great.

next, it’s up to you whether you handle the second input. In your code, you can just look only at the first input

if use “Input System UI Input Modoule” , check this component , change Pointer Behavior to Single Unified Pointer