A group of friends and I played a few years back and we found the natural end was when we could survive the hardest of the blood moons in our base without having any damages or breakthroughs and could easily beat any of the areas that were supply runs. We also had built multiple vehicles so we would bomb through in a convoy to wherever we were going and clear everything.
That was the end because we didn’t want to play anymore.
I don’t think there has, I only played a few times but it always seemed like such a rich story and setting for adventures. A world magically ripped apart by the billions of lives extinguished instantly in nuclear fire. Dimensional Beings crossing into the world, from dragons to vampires to leyline walkers.
For MGSV if you haven’t cheated yet I suggest it just for the money at least. Download a cheat table and run cheat engine. I don’t like the base building parts of games so I just blew through that by giving myself all the money.
That way I can just do the mission parts of the game without caring what is going on at mother base.
Wellness checks to be sent to their homes to check on their real daughters?