Save And load Level Data in a game with one game scene and multiple levels saved as prefabs

I've heard Resource Folder calls are bad, but I don't see the harm in using them for this. You will only be making one call at a time, so it's not bad. Here's what you need to do. You need to create a class called LevelData. Store the information about stars, time, and other stats like that onto it. You also want to store the relative path of the Prefab as a string in the class as well. You will then have a list of these that need to be saved and loaded from a GameManager class which inherits from MonoBehaviour. I think the easiest route for you is to have the GameManager class have a list of LevelData, make sure it is marked with [System.Serializable], and then you can edit these values to be whatever you want within the Inspector. GameManager will serialize all of this data, so that's not a problem, however these changes won't persist. To get the data to persist, you need to save these changes to a file in some directory; I recommend Application.persistentDataPath. Whenever you start the game, it should check to see if the file exists. If it does, you will load the list from the file. This will override all of the settings you had made in the editor, which is what you want. That means the data persisted. The data you create in the editor should only be the INITIAL list. You will have issues of adding new levels and stuff, but these can be avoided by creating a custom loader. For example, you could load the list that's in the file, check to see if the current list already has a reference to the same scene, and override it's values. That way, if you added something in the editor after already saving data that the change wasn't apart of, it won't override your new levels and stuff that you're trying to add to the game. I hope this helps, but I'm here if you have more questions!