scroll.StopMovement()

public class ScrollSpeedClamp : MonoBehaviour {
    //clamps inertia of scroll rects to cease updating when the speed is below a certain threshold
    private void Start() {
        ScrollRect[] allScrolls = GameObject.FindObjectsOfType<ScrollRect>();
        foreach (ScrollRect scroll in allScrolls.Where(x => x.inertia)) {
            ScrollRect self = scroll;
            scroll.onValueChanged.AddListener((v) => OnScroll(self, v));
        }
    }

    private static Dictionary<ScrollRect, Vector2> lastScrollPosition = new Dictionary<ScrollRect, Vector2>();
    private static void OnScroll(ScrollRect scroll, Vector2 v) {
        if(lastScrollPosition.ContainsKey(scroll)) {
            Vector2 last = lastScrollPosition[scroll];
            lastScrollPosition[scroll] = v;
            if((last - v).sqrMagnitude > 1f) return;
            scroll.StopMovement();
            Debug.Log($"JUST STOP ALREADY! D: {v.y}");
        }
        else {
            lastScrollPosition.Add(scroll, v);
        }
    }
}