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

[Absimiliard]

And yeah, I understand what you mean here... Temporal paradoxes truly are complicated to deal with, but you've convinced me of the Graha tia thing. But I'm STILL not convinced on the Elidibus thing! I truly believe he meant what I said earlier, he even goes as far as to explain the reason why we're not capable of altering the course of time "For the reality you wish to save - the reality to which you must return - exists as a result of the Final Days. You cannot reshape the past to undo the tragedies of the present. Cannot unmake the sorrow and suffering fated to come."

And yet we've got these little gems from the conversation just before Elidibus has you prep the tower for opening the gate. Pardon the poor quality. I'm having connection issues out the wazoo at the moment, so I yoinked it from a random YouTube video instead of just watching the cutscene again in-game.



Even the man himself recalls the WoL from Elpis. For someone that couldn't make any changes to the timeline, they certainly seem to have left a lasting impact. I should think this would also answer your question about whether or not Venat is also the same one. It's already been established the Emet-Selch and Hythlodaeus encountered by the WoL in Elpis are the same, and Elidibus clearly retains at least fragments of memories of their having met. If this is the case, then it basically can't be a different Venat. For his part, it was this memory which motivated Elidibus to sacrifice his very existence so the WoL could make the journey to Elpis. The act didn't just kill him -- it unmade him. He's every bit as permadead as Venat so far as I am aware.

As for Elidibus' comments about making changes; they could just as easily be interpreted as a warning. For if you were to make changes in such a way as to prevent the sundering or otherwise change any circumstances leading up to the present, you may not have a world to return to at all. Or if you did, it might not be yours. ....Or you might simply cease to exist, which would by default undo whatever you did. Luckily, the predestination paradox is there to prevent you from ruining everything. Then we've the previously discussed option of him simply not realizing Emet-Selch was going to reinforce your aether and thereby give you the ability to meaningfully interact with the world of the past.

There's a veritable mountain of evidence in favor of this indeed being a causal loop. While it's entirely possible Yoshi P. might pop up at some point to dismiss this, doing so would rather handily undermine the entirety of Endwalker.