My player is lagging/stuttering when trying to move mid-air(after jumping)

Questions & Answers
1

Here is my code:

[RequireComponent(typeof(Rigidbody))]
public class PlayerMovement : MonoBehaviour
{
    public float _speed;
    public float jumpForce;
    private bool isGrounded;
    public Vector3 jump;
    
    
    Rigidbody rb;
    void Start()
    {
        rb = GetComponent<Rigidbody>();
        jump = new Vector3(0.0f, 2.0f, 0.0f);
    }
    
    


    private void OnCollisionStay(Collision collision)
    {
        isGrounded = true;
        
    }

    private void OnCollisionExit(Collision collision)
    {
        isGrounded = false;
        
    }
    void Update()
    {

        float horizontalInput = Input.GetAxis("Horizontal");
        float verticalInput = Input.GetAxis("Vertical");
        transform.Translate(new Vector3(horizontalInput, 0, verticalInput) * _speed * Time.deltaTime);

        if (Input.GetKeyDown(KeyCode.Space) && isGrounded == true)
        {
            rb.AddForce(jump * jumpForce, ForceMode.Impulse );

        }


    }

        


  
}

Note: The higher the jump is, the bigger the lag/stuttering gets
I’m a total beginner and i’ve been trying to figure this out for the last 3 hours but I just can’t find the problem.
I thought it was because of the camera and tried to build the game but it lags anyways

2

Because you use the RigidBody’s Forces together with Transform.Translate(). You make jumps only with Transform.Translate() which is a little hard, or you move Character in all directions using only the Rigidbody’s forces;