UnityでNullReferenceExceptionエラーが解決できない

実現したいこと

Unityで2Dゲームを制作しています。
チュートリアル動画( https://youtu.be/vY0Sk93YUhA?si=77TRM4O89HVe_m6E )に従って会話ウィンドウを実装しようとしています。
具体的には、PlayerがNPCに近づくとplaerInRangeというboolがtrueになり、その状態でPlayerInputで設定したinteractキーを押すと会話が始まるという機能を実装したいです。

発生している問題・分からないこと

動画内のTriggering Dialogueチャプターの所までのコードを書き実行したところ、NPCに近づいた瞬間ゲームがエラーを吐き停止してしまいます。検証した結果、

if(InputManager.GetInstance().GetInteractPressed())
{
Debug.Log(inkJSON.text)
}

の部分が問題のようです。
関係があると思われるInputManagerのコードも付しておきます。

エラーメッセージ

error
1NullReferenceException: Object reference not set to an instance of an object
2DialogueTrigger.Update () (at Assets/scripts/Dialogue/DialogueTrigger.cs:26)

該当のソースコード

DialogueTrigger
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4
5public class DialogueTrigger : MonoBehaviour
6{
7    [Header("Visual Cue")]
8    [SerializeField] private GameObject visualCue;
9
10    [Header("Ink JSON")]
11    [SerializeField] private TextAsset inkJSON;
12
13    private bool playerInRange;
14
15    private void Awake()
16    {
17        playerInRange = false;
18        visualCue.SetActive(false);
19    }
20
21    private void Update()
22    {
23        if (playerInRange)
24        {
25            visualCue.SetActive(true);
26            if (InputManager.GetInstance().GetInteractPressed())
27            {
28                Debug.Log(inkJSON);
29            }
30        }
31        else
32        {
33            visualCue.SetActive(false);
34        }
35    }
36
37    private void OnTriggerEnter2D(Collider2D collider)
38    {
39        if(collider.gameObject.tag == "Player")
40        {
41            playerInRange = true;
42        }
43    }
44
45    private void OnTriggerExit2D(Collider2D collider)
46    {
47        if (collider.gameObject.tag == "Player")
48        {
49            playerInRange = false;
50        }
51    }
52}
53

InputManager
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4using UnityEngine.InputSystem;
5
6// This script acts as a single point for all other scripts to get
7// the current input from. It uses Unity's new Input System and
8// functions should be mapped to their corresponding controls
9// using a PlayerInput component with Unity Events.
10
11[RequireComponent(typeof(PlayerInput))]
12public class InputManager : MonoBehaviour
13{
14    private Vector2 moveDirection = Vector2.zero;
15    private bool jumpPressed = false;
16    private bool interactPressed = false;
17    private bool submitPressed = false;
18
19    private static InputManager instance;
20
21    private void Awake()
22    {
23        if (instance != null)
24        {
25            Debug.LogError("Found more than one Input Manager in the scene.");
26        }
27        instance = this;
28    }
29
30    public static InputManager GetInstance()
31    {
32        return instance;
33    }
34
35    public void MovePressed(InputAction.CallbackContext context)
36    {
37        if (context.performed)
38        {
39            moveDirection = context.ReadValue<Vector2>();
40        }
41        else if (context.canceled)
42        {
43            moveDirection = context.ReadValue<Vector2>();
44        }
45    }
46
47    public void JumpPressed(InputAction.CallbackContext context)
48    {
49        if (context.performed)
50        {
51            jumpPressed = true;
52        }
53        else if (context.canceled)
54        {
55            jumpPressed = false;
56        }
57    }
58
59    public void InteractButtonPressed(InputAction.CallbackContext context)
60    {
61        if (context.performed)
62        {
63            interactPressed = true;
64        }
65        else if (context.canceled)
66        {
67            interactPressed = false;
68        }
69    }
70
71    public void SubmitPressed(InputAction.CallbackContext context)
72    {
73        if (context.performed)
74        {
75            submitPressed = true;
76        }
77        else if (context.canceled)
78        {
79            submitPressed = false;
80        }
81    }
82
83    public Vector2 GetMoveDirection()
84    {
85        return moveDirection;
86    }
87
88    // for any of the below 'Get' methods, if we're getting it then we're also using it,
89    // which means we should set it to false so that it can't be used again until actually
90    // pressed again.
91
92    public bool GetJumpPressed()
93    {
94        bool result = jumpPressed;
95        jumpPressed = false;
96        return result;
97    }
98
99    public bool GetInteractPressed()
100    {
101        bool result = interactPressed;
102        interactPressed = false;
103        return result;
104    }
105
106    public bool GetSubmitPressed()
107    {
108        bool result = submitPressed;
109        submitPressed = false;
110        return result;
111    }
112
113    public void RegisterSubmitPressed()
114    {
115        submitPressed = false;
116    }
117
118}