how to disable a another script after it runs.

You can use events to trigger things, then just listen for those events in another class, or the same class:

 System.Action SomethingHappened;
 if (SomethingHappened != null) { SomethingHappened(); }

You would put this at the end of your logic that determines when the object has actually finished its objective. You will need to do a check to see that the object is at the position you want, don't do a position == vector check, it won't work. Do a distance check with a range that you consider ok.

I realized I should add a little more to help you out with this (put something like this at the end of your update):

 public System.Action FinishedMovement;
 float threshold = 0.1f;
 
 void Update() {
 
   // Blah blah tranform.position.MoveToward(blahblah)
 
   if (Vector3.Distance(targetVector, transform.position) <= threshold) {
      if (FinishedMovement != null) { FinishedMovement(); }
   }
 }