Added a solution based on inheritance

Inheriting from this abstract class insteead of a NetworkBehaviour allows a script to be disabled on Awake and only enabled in a client or a server specifically

Author: LPLafontaineB

Assets/BossRoom/Scripts/Shared/RoleRestrictedNetworkBehaviour.cs

@@ -0,0 +1,47 @@
+using System;
+using Unity.Netcode;
+using UnityEngine;
+
+/// <summary>
+/// NetworkBehaviour that is only enabled when spawned, on either the server or a client.
+/// </summary>
+public abstract class RoleRestrictedNetworkBehaviour : NetworkBehaviour
+{
+    /// <summary>
+    /// Returns the role for which this NetworkBehaviour should be enabled.
+    /// </summary>
+    /// <returns></returns>
+    protected abstract Role GetTargetRole();
+
+    protected enum Role
+    {
+        Client,
+        Server
+    }
+
+    void Awake()
+    {
+        // Disable this NetworkBehaviour until it is spawned
+        enabled = false;
+    }
+
+    public override void OnNetworkSpawn()
+    {
+        // enable this NetworkBehaviour only for the target role
+        switch (GetTargetRole())
+        {
+            case Role.Client:
+                enabled = IsClient;
+                break;
+            case Role.Server:
+                enabled = IsServer;
+                break;
+        }
+    }
+
+    public override void OnNetworkDespawn()
+    {
+        // Disable This NetworkBehaviour again, until it is either destroyed or spawned again
+        enabled = false;
+    }
+}