Need help creating ai movement

i am using this but what di i add to make it slowly turn instead of just snapping

 using UnityEngine;
  using System.Collections;
  
  public class Test: MonoBehaviour {
      public Vector3 targetPos;
      public bool isMoving = false;
      public float maxRange = 10f;
      public float waitTime = 3f;
      public float speed = 0.05f;
      
      void Update() {
          if(isMoving == false) {
              FindNewTargetPos();
          }
      }
      
      private void FindNewTargetPos() {
          Vector3 pos = transform.position;
          targetPos = new Vector3();
          targetPos.x  = Random.Range(pos.x - maxRange, pos.x + maxRange);
          targetPos.y = pos.y;
          targetPos.z = Random.Range(pos.z - maxRange, pos.z + maxRange);
  
          transform.LookAt(targetPos);
          StartCoroutine(Move());
      }
      
      IEnumerator Move() {
          isMoving = true;
          
          for (float t = 0.0f; t < 1.0f; t += Time.deltaTime * speed) {
  
              transform.position = Vector3.MoveTowards(transform.position, targetPos, t);
              yield return null;
          }
          
          yield return new WaitForSeconds(waitTime);
          isMoving = false;
          yield return null;
      }
      
      
      
  }