Can't add light to script

Hey, so I'm trying to add a day/night cycle to my game and I can't add a light anything to a script even though i specified that the object I want to change is a type=light and a directional light. I followed a simple 6 minute youtube tutorial here: https://www.youtube.com/watch?v=m9hj9PdO328&t=300s The code is here:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 [ExecuteAlways]
 public class LightingManager : MonoBehaviour
 {
     //References
     [SerializeField] private Light DirectionalLight;
     [SerializeField] private LightingPreset Preset;
     //Variables
     [SerializeField, Range(0, 24)] private float TimeOfDay;
 
     private void Update()
     {
         if (Preset == null)
             return;
         if (Application.isPlaying)
         {
             TimeOfDay += Time.deltaTime;
             TimeOfDay %= 24;
             UpdateLighting(TimeOfDay / 24f);
         }
     }
     private void UpdateLighting(float timePercent)
     {
         RenderSettings.ambientLight = Preset.AmbientColor.Evaluate(timePercent);
         RenderSettings.fogColor = Preset.FogColor.Evaluate(timePercent);
         if (DirectionalLight != null)
         {
             DirectionalLight.color = Preset.DirectionalColor.Evaluate(timePercent);
             DirectionalLight.transform.localRotation = Quaternion.Euler(new Vector3((timePercent * 360f) - 90f, 170, 0));
         }
     }
     private void OnValidate()
     {
         if (DirectionalLight != null)
             return;
         if (RenderSettings.sun != null)
         {
             DirectionalLight = RenderSettings.sun;
         }
         else
         {
             Light[] lights = GameObject.FindObjectsOfType<Light>();
             foreach (Light light in lights)
             {
                 if (light.type == LightType.Directional)
                 {
                     DirectionalLight = light;
                     return;
                 }
             }
         }
     }
 }

This also contains some code for the lighting preset:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 [System.Serializable]
 [CreateAssetMenu(fileName ="Lighting Preset", menuName ="Scriptables/Lighting Preset",order =1)]
 public class LightingPreset : ScriptableObject
 {
     public Gradient AmbientColor;
     public Gradient DirectionalColor;
     public Gradient FogColor;
     void Start()
     {
         
     }
 
     void Update()
     {
         
     }
 }

I'd really appreciate if someone helped with the issue, thanks! P.S. I get no errors in visual studio.