Time Management. Morning, noon and night.

What I would do is use an enum to represent the time of day. I wrote an example script, showing how you can use a TimeManager class to progress to the next time of day (as well as keep track of how many days are elapsed). There's example usage of both, but the examples are very simple -- you'll need to figure out how you want to use the time of day and when you want your player to progress in your own game:

 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using UnityEngine;
 
 public enum TimeOfDay
 {
     Morning,
     Noon,
     Night
 }
 
 public static class TimeManager 
 {
     public static int DaysElapsed { get; private set; }
 
     public static TimeOfDay CurrentTimeOfDay { get; private set; }
 
     public static void ProgressToNextTime()
     {
         switch(CurrentTimeOfDay)
         {
             case TimeOfDay.Morning:
                 CurrentTimeOfDay = TimeOfDay.Noon;
                 break;
             case TimeOfDay.Noon:
                 CurrentTimeOfDay = TimeOfDay.Night;
                 break;
             case TimeOfDay.Night:
                 CurrentTimeOfDay = TimeOfDay.Morning;
                 DaysElapsed = DaysElapsed + 1;
                 break;
         }
     }
 }
 
 // an example class doing something with the time
 public class GameManager : MonoBehaviour
 {
     // an example of using the time of day to return something different
     // your real "GetActions" would probably return a list of Action classes or something similar
     public string GetAction()
     {
         var currentTimeOfDay = TimeManager.CurrentTimeOfDay;
         switch(currentTimeOfDay)
         {
             case TimeOfDay.Morning:
                 return "Breakfast";
             case TimeOfDay.Noon:
                 return "Lunch";
             case TimeOfDay.Night:
                 return "Dinner";
             default:
                 return string.Empty;
         }
     }
 
     // an example of incrementing the time after an action
     public void DoAction(string action)
     {
         // here, the player's action is just printing debug info
         Debug.Log("Player did the action: " + action);
 
         // after the player does the action, use this to increment the time
         TimeManager.ProgressToNextTime();
     }
 }