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

[Iscah]

Trying to find a justification rather than a plot hole (because whether we like the story or not, we're stuck with it and I'd rather make it make sense), it strikes me that whatever Kairos does to erase the subject's memories in the first place could easily also obliterate any Echo-traces hanging in the air around it.

It's also possible that Venat went on the run after this, and nobody from the Convocation ever caught up to her to ask the difficult questions.

(Oops, this was replying to someone several pages back. I thought I was in another thread that I was more up-to-date on. They're all starting to look the same.)