Rigidbody like movement for Vector3.MoveTowards Nav

So I have been trying to make a game where you scare sheep away into pens, I have the basic movement down where the sheep moves on a Navmesh and runs away from player. but want them to act like Rigidbody balls rolling along the ground, any help is greatly appreciated :)

   using System.Collections.Generic;
     using UnityEngine;
     
     public class Sheep: MonoBehaviour 
     {
         public Transform posPlayer;
         public float closeDistance = 5.0F;
         public float speed = 1.0F;
         public float rotateSpeed = 2.0F;
         void Start()
         {
             posPlayer= GameObject.FindWithTag("Player").transform;
         }
     
         void Update() 
         {
             if (other)    
             {
                 Vector3 offset = posPlayer.position - transform.position;
                 float sqrLen = offset.sqrMagnitude;
                 if (sqrLen < closeDistance * closeDistance)
                 {
                     float step = -speed * Time.deltaTime;
                     float RoStep = -rotateSpeed * Time.deltaTime;
                     Vector3 targetDir = posPlayer.position - transform.position;
                     Vector3 newDir = Vector3.RotateTowards(transform.forward, targetDir, RoStep, 0.0F);
                     Debug.DrawRay(transform.position, newDir, Color.red);
                     transform.rotation = Quaternion.LookRotation(newDir);
                     transform.position = Vector3.MoveTowards(transform.position, posPlayer.position, step);
                     transform.eulerAngles=new Vector3(0,transform.eulerAngles.y,transform.eulerAngles.z);
 //Just for Debug
 print ("Player is close, Running Away");
                 }
     
             }
     
         }
     
     }