[Misc] Singleton pattern improvements, get rid of warnings and errors

Assets/Scripts/Input/InputManager.cs

@@ -8,18 +8,20 @@ using UnityEngine.InputSystem;
 public class InputManager : MonoBehaviour
 {
     private static InputManager _instance;
+    private static bool _isQuitting = false;
+
     public static InputManager Instance
     {
         get
         {
-            if (_instance == null)
+            if (_instance == null && Application.isPlaying && !_isQuitting)
             {
                 _instance = FindAnyObjectByType<InputManager>();
                 if (_instance == null)
                 {
                     var go = new GameObject("InputManager");
                     _instance = go.AddComponent<InputManager>();
-                    DontDestroyOnLoad(go);
+                    // DontDestroyOnLoad(go);
                 }
             }
             return _instance;
@@ -36,7 +38,7 @@ public class InputManager : MonoBehaviour
     void Awake()
     {
         _instance = this;
-        DontDestroyOnLoad(gameObject);
+        // DontDestroyOnLoad(gameObject);
         playerInput = GetComponent<PlayerInput>();
         if (playerInput == null)
         {
@@ -70,6 +72,11 @@ public class InputManager : MonoBehaviour
         }
     }
 
+    void OnApplicationQuit()
+    {
+        _isQuitting = true;
+    }
+
     /// <summary>
     /// Sets the default ITouchInputConsumer to receive input events.
     /// </summary>