Some questions after finishing the game (massive spoilers)

[Madscientist]

I have finished the game and I saw endings ABCDE.
But some questions are still open.
note: I have played only this game, not the other ones of the series.

To understand things, I tried to make a timeline:
- humans get extincted, only self aware androids as intelligent "life" on earth
- Aliens attack earth with machines, androids and machines fight
- Machines kill aliens (*1)
- Yorha project is created to improve android morale by making them believe that humans are still alive (*2)
- Machines want to destroy humans on moon (Adam and Eve say so. This means the machines belief the propaganda too. They do not know that all humans are dead, though humans got extincted before arrival of machines.)
- In the end, all yorha androids dead and machine network destroyed (ending C) or gone (ending D). Only 2B, 9S and A2 could be alive (ending E). Only androids and machines (not connected via network) remain on earth.

*1: Why do androids and machines continue to fight for millennia when both humans and aliens are dead? Both sides have nothing to fight for.
If I understand the red girls correctly, the machine network wants the war to continue forever because it considers conflict as the driving force for evolution. But I am not 100% sure.

*2: Who created yorha?
The commander knows that the humans on the moon are a lie, but even she does not know everything. ( After the destruction of the bunker we find data that were secret even for the commander, such as the fact that it was intended from the beginning to destroy all yorha stuff to make sure nobody learns the truth (humans are dead.)) Except the commander and Anemone we never meet anyone who could be considered the leader of androids.

- What does yorha mean anyway?
It looks like a shortcut for something.

- Why are the machines obsessed with failure and suicide?
Are they just tired of fighting forever for no reason?
some examples:
- 9S finds out that machines copy human behavier and repeat the same mistakes all the time.
- Many machines jump into a valley to commit suicide. We have a quest to kill the survivours.
- Engels kills himself after we talk to him.
- Some machines start a suicide cult, trying to kill all other machines who do not want to die before kiiling themselves.
- Machine children kill themselves even though we can protect them from hostile machines.

[Cacosubthree]

1. Why did the androids and machines kept fighting? Androids was still fighting because it is in their basic programming to protect humanity and its legacy, and they got lied to that humans are still alive. Machines fight because their sole purpose in life is to "defeat the enemy" which caused a parodox, if you read Jackass' report you receive after getting ending C or D.

2. Who created YoRHa? This game has a lot of side content that expands the story. Read this to answer your question.
https://theark.wiki/w/Project_YoRHa

What does YoRHa mean? If I recall correctly, Yorha is a Japanese word that means passinh leaves. It is poetic if give it some thought. The random capitalization has no confirmed meaning.

The machine suicide thing is just a thing that happens when the existential crisis hits hard on you I think. Both the machines and androids lost the purpose of thier existence. For the androids it is to protect humanity. For machines it is to defeat the androids, which is something they are not willing to accomplish to some extent. In philosophical terms, their god died and it was up to them to find purpose in a meaningless existence. And when one failed to find a purpose, some chooses to just end that meaningless existence.

[Scheneighnay]

1. because otherwise they would have no purpose and fall into stagnation

2. prior androids