I think I may need to rename the "endings." I have them in numerical order to give a sense of where you are, but you can absolutely blitz past them without losing out on anything.
4 and 5 are mutually exclusive, and I won't spoil why for new players. The important part is that if you get 4, you still have more to do. If you get 5, you've met the same conditions as 4, but you've also progressed far enough into the later game content.
That progression is the gate, not something else you need to find.