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

[Lelila38]

The issue here is that it creates a time paradox that just raises more questions. We get told we can't change the past, yet we clearly do it by telling stuff to Venat. We either accept it an issue or buy in a time paradox that infinitely repeats itself.

Another issue I have with that is that the past has allegedly been changed already by G'Raha when he used the Crystal Tower and became the Exarch. As we know from the short stories, his original timeline persisted and wasn't altered by his actions.
So why does the same not apply to Elpis?