How to smoothen FPS movement (keyboard)

Hi,

I'm making a 3d FPS game in Unity and I have this code so far for the movement:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerMovementController : MonoBehaviour
 {
     [SerializeField] private float speed;
     [SerializeField] private float jumpForce;
 
     [SerializeField] private float rayCastDist;
     private Rigidbody rigidbody;
 
     private void Start(){
         rigidbody = GetComponent<Rigidbody>();
         
     }
 
     private void Update(){
         Jump();
     }
 
     private void FixedUpdate(){
         Move();
     }
 
     private void Move(){
         float hAxis = Input.GetAxis("Horizontal");
         float yAxis = Input.GetAxis("Vertical");
 
         Vector3 movement = new Vector3(hAxis, 0, yAxis) * speed;
         Vector3 newPos = rigidbody.position + rigidbody.transform.TransformDirection(movement);
 
         rigidbody.MovePosition(newPos);
     }
 
     private void Jump(){
        if (Input.GetKeyDown(KeyCode.Space)){
            if (IsGrounded()){
                 rigidbody.AddForce(0, jumpForce, 0, ForceMode.Impulse);
            }
        } 
     }
 
     private bool IsGrounded(){
         return (Physics.Raycast(transform.position, Vector3.down, rayCastDist));
     }
     
 }
 

When I run this, my player (a capsule) moves with my key inputs. But, it is a bit choppy. For example, when I press an arrow key, the player moves abruptly with a jolt after like 3/4 of a second. Can someone please help me with how I can smoothen this movement? thanks.