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

[Absimiliard]

It's called a bootstrap paradox. For it to exist someone or something (it can even be raw information) must travel into the past and change things in a way that both leads to and requires the aforementioned time travel to occur in the first place. It has no defined beginning or end as a result. At a base level the key players in maintaining a bootstrap paradox operate in ignorance and therefore lack agency, but this can change when one or more parties are somehow made aware of what's happening. The paradox becomes consensual the moment even one of the participants necessary for its perpetuation is afforded knowledge and therefore agency, although the prospect of breaking one of these opens some very migraine-inducing cans of worms.

[Turtledeluxe]

It's called a bootstrap paradox. For it to exist someone or something (it can even be raw information) must travel into the past and change things in a way that both leads do and requires the aforementioned time travel to occur in the first place. It has no defined beginning or end as a result. At a base level the key players in maintaining a bootstrap paradox operate in ignorance and therefore lack agency, but this can change when one or more parties are somehow made aware of what's happening. The paradox becomes consensual the moment even one of the participants necessary for its perpetuation is afforded knowledge and therefore agency, although the prospect of breaking one of these opens some very migraine-inducing cans of worms.

Yes but the one with agency in this case is us, the time traveler. And we possibly create the bootstrap paradox with Hydaelyn. Can we really say where the idea of Hydaelyn came from? It's the player, in the absence of an og timeline. All of this is highlighted in the conversation where we confess the truth to Venat and Co.

In relation to Venat, when I say lack of agency that does not mean ignorance. It means lack of agency. She is not capable of changing what is fated to happen even if she tries. Whether she accelerates or deescalates.

And it's worth noting for Venat she's the most anxious to change the future and believes the WoL immediately. She's aggressively interested in changing fate but she doesn't. She goes from "Nothing is impossible. This I have always believed. And if Hydaelyn is indeed me she would believe the same." to "Faced with Zodiark I had no choice but to render him asunder".

Also she has no way to avert the start the Final Days. As soon as we get close, Meteion goes nuts and Hermes does the deed. Imo this is just further evidence that even if someone is actively working on a solution, it's going to happen anyway one way or another.