Saving a class List from another script

So i want to make an inventory Save and Load System, each item gets stored in a List of type Item. But when i try to acces that List i get an Nullrefernce Exception Error.

PlayerData Script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 [System.Serializable]
 public class PlayerData
 {
     public int money;
     public List<Item> itemList;
 
     public PlayerData(PlayerManager manager)
     {
         itemList = manager.inventory.itemList;
         money = manager.money;
     }
 }

PlayerManager where the data gets Loaded:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerManager : MonoBehaviour
 {
     [SerializeField] public UI_Inventory uiInventory;
 
     public Inventory inventory;
 
     [Header("PlayerRelatedData")]
     public int money;
 
     private void Awake()
     {
         inventory = new Inventory();
 
         uiInventory.SetPlayer(this);
         uiInventory.SetInventory(inventory);
     }
 
     private void OnTriggerEnter2D(Collider2D collision)
     {
         ItemWorld itemWorld = collision.GetComponent<ItemWorld>();
         if(itemWorld != null)
         {
             inventory.AddItem(itemWorld.GetItem());
             itemWorld.DestroySelf();
         }
     }
 
     public Vector3 GetPosition()
     {
         return gameObject.transform.position;
     }
 
     public void SavePlayer()
     {
         SaveSystem.SavePlayer(this);
     }
 
     public void LoadPlayer()
     {
         PlayerData data = SaveSystem.LoadPlayerData();
         inventory.itemList = data.itemList;
 
         money = data.money;
     }
 }

SaveSystem itself:

 using System.IO;
 using UnityEngine;
 using System.Runtime.Serialization.Formatters.Binary;
 
 public static class SaveSystem
 {
     
     public static void SavePlayer(PlayerManager manager)
     {
         BinaryFormatter formatter = new BinaryFormatter();
 
         string path = Application.persistentDataPath + "/player.savedData";
         FileStream stream = new FileStream(path, FileMode.Create);
 
         PlayerData data = new PlayerData(manager);
 
         formatter.Serialize(stream, data);
         stream.Close();
     }
 
     public static PlayerData LoadPlayerData()
     {
         string path = Application.persistentDataPath + "/player.savedData";
         if (File.Exists(path))
         {
             BinaryFormatter formater = new BinaryFormatter();
             FileStream stream = new FileStream(path, FileMode.Open);
 
             PlayerData data = formater.Deserialize(stream) as PlayerData;
             stream.Close();
 
             return data;
         }
         else
         {
             Debug.LogError("Save File not found in" + path);
             return null;
         }
     }
 
 }

Would be really thankful if anybody could help me here.