Does anyone know if there’s any built in functions for Unity to save entire scenes and everything in them? ( instantiated prefabs, object variables, ect. ). So being able to close the game and then open it with everything being exactly where it was with all their correct variable values.
No, you have to handle saving and loading for a game yourself.
There are some assets on the Asset Store that may make this easier for you, just make sure you get something suitable for your needs. As I remember, several are free, so you can take a look at their code and see how they are handling things.
If you’re saving that much information, I’d strongly recommend not using the default Player Prefs thing as it saves into the Windows Registry. Generally safer and more polite to have actual save files.
Pretty sure your options are to write in those features yourself or use asset packages like the unity serializer.