2D Game has very bad lag because of one script?

I am making somewhat of a flappy bird clone (mostly for practice) and everything works fine, but it is just really slow with a low FPS of 13 and a max FPS of 28. Why would this be?

So I ran a check with the unity profiler and it turns out that my MoveLeft script which I am using to reuse my obstacles is taking up 73% of the CPU. I have it attached to each of my 6 prefabs, which include 2 long obstacles and a token (to collect) in middle each. The game works by moving the prefabs along the camera, then moving them back after they pass the camera.

Here is the script:

 using UnityEngine;
 using System.Collections;
 
 public class MoveLeft : MonoBehaviour
 {
 
     [SerializeField]
     private float _speed = 5f;
     // Update is called once per frame
     void Update()
      {
          transform.Translate(Vector3.left * Time.deltaTime * _speed);
          if (transform.position.x < -15)
          {
              float randomYPosition = UnityEngine.Random.Range(-3, 3);
              transform.position = new Vector3(15, randomYPosition, 0);
          }
      } 
 }

Any help is appreciated! Thank you!!