What's the point with that quite lackluster story in Endwalker?

[Lauront]

You....don't care that if she hadn't done what she did you and your ENTIRE reality would not exist? Are you actually being serious? Your entire reality would cease to exist along with you which would also have the added consequence of creating a time paradox.

All this would actually be relevant if AUs didn't form in this setting... but they do. And hey, if it's good enough for the Ironworks to make a decision like that for a "brighter tomorrow", my character could roll those dice, too...

Even Eldibus tells you you cannot change the past no matter what you do. There was nothing else she could do other than what was destined to happen. And the writers never let you forget Emet is a villain? They could not be sublte in beating you over the head that he's really a good boy who just did bad things. Even Darth Vader was not this blatantly whitewashed and Darth Vader didn't even do as much evil. Vader only blew up one world. Emet blew up, what was it, 8?

And yet she says she will take nothing for granted.

Venat: Heavy will weigh the burden of guiding this legion of souls...
Venat: Yet I have faith in mankind's potential. As long as he believes in himself, there is naught he cannot achieve. So I will not give up on him. On us.
Venat: You may find your world to be very different. Or perhaps the erasure of our friends' memories has sown the seeds of a conjunction between us.
Venat: We cannot know until the moment is at hand. So shall I strive to do my best, taking naught for granted as I walk my path.

At this point, we know the Exarch did not cease to exist as well even though his timeline had been averted. Even if Elidibus does not fully grasp the implications of this, the MC is cognisant of this fact and it is offered up as a possibility from G'raha himself. Really, the issue here is why employ time travel yet again, and then not make use of the one advantage it could provide over other methods (e.g. using the Echo to show flashbacks of the past), which is to allow for an AU... and they keep this gate to Elpis open so you can go back to do Pandaemonium to add injury to insult.

The rest of your post is just bizarre. Emet-Selch is shown as his ancient persona to underscore how much he changed by SHB. The entire crew of Scions with you in the Tempest is against him, ranting against him, and your character challenges him. EW showcases his persona before all this. It is not a "whitewash", it is a: here is how having your entire civilisation and planet shattered while having no understanding why (due to a memory wipe) can change you. You keep trying to bring up Emet's actions but you refuse to acknowledge or deal with the fact that she allowed for it all; whether that was "necessary" to preserve the timeline or not, she took the conscious action to enable it.

Your problem is you're mad that she wasn't just blatantly villified and treated as such by us. Zero moral ambiguity, just straight up "Hydaelin evil".

But Emet is fine. Okay. You literally kill her and destroy her soul. Emet doesn't even get such a horrible fate.

Pure strawmanning of that poster at this point. There is not a single negative reaction to her actions, barring Y'shtola not questioning her words - and even then, she wishes to re-cast them in a positive light. As Kaoru mentions, even Emet in an out of character fashion, blunts any criticism he has to praise her. And if I may correct you on a point: you aren't the one who decides to kill her - she decides to draw on her remaining life energy to "test" the group. This happens by her will, much as it is Emet's decision to confront the WoL.

I think I see the issue here...you're currently believing it was only for YOUR life. It was not...it was for the lives of all that would follow, not just yours. The Ancients in the flashbacks showed they were willing to sacrifice newer life (meaning essentially children) to safeguard their own way of life. Venat and the ones with her who summoned Hydaelyn were against that, feeling that they should do everything in their power to leave things to the newer life and safeguard them.

Hmm no, it doesn't mean "essentially children". It is heavily implied from the JP version of the Hyth dialogue to be "life" seeded by Zodiark. Knowing what we do now of how the ancients created life, this is likely to be beings similar to those in Elpis, i.e. creations fit to gain souls. Nowhere is any indication given that these would be ancients. It's at the point where I am beginning to think, given her penchant for lying to achieve outcomes she desired, that she took advantage of this whole issue to set up opposition to the sacrifices as before the Anamnesis Anyder scene (noting she does not chide the Convocation for them... kinda odd if this is child sacrifice of their own), there was more widespread opposition to them. We now know that her opposition to the sacrifices is instrumental, in the sense that they would enable restoration of the ancient civilisation and her concern is, above all else, the ancients heading for a fate like the Plenty; that is why she opposes them.