'Moving' a fixed Distance to the left/right

I want to create a Game, where your Character has to Dodge blocks etc. on 3 Diffrent Lanes(f.e. like Subway Surfer) I just cant figure out how to set a fixed Distance for my Character to move. (Note that my Character will be constantly moving forward). I have setup a Level, where you spawn on a huge cube(0,0,0). How can i tell Unity to move my Character EXACTLY 30 to X?

 public class burgerController : MonoBehaviour
     {
     // speed is set on 5 in the Editor.
     public float speed;
     public int counter = 0;
      
 void Update()
 {

  transform.Translate(Vector3.forward * speed * Time.deltaTime, Space.World);
 
  if (counter >= 0)
  {
      if (Input.GetKeyDown("a"))
      {
          transform.Translate(new Vector3(-30, 0, 0) * speed * Time.deltaTime, Space.World);
          counter--;
      }
  }
  if (counter <= 0)
  {
      if (Input.GetKeyDown("d"))
      {
          transform.Translate(new Vector3(30, 0 , 0) * speed * Time.deltaTime,Space.World);
          counter++;
      }
  }
  if (counter == -1)
  {
      if (Input.GetKeyDown("s"))
      {
          transform.Translate(new Vector3(30, 0, 0) * speed * Time.deltaTime, Space.World);
          counter = 0;
      }
  }
  if (counter == 1)
  {
      if (Input.GetKeyDown("s"))
      {
          transform.Translate(new Vector3(-30, 0, 0) * speed * Time.deltaTime, Space.World);
          counter = 0;
      }
  }

}

I have tried several Ways to fix this and just couldnt find a Solution, it is really Important and i would appreciate your help. (my Character is just a sphere btw. (1/1/1 Scale) everything is setup really simple in my Level)