Ouroboros
I think that's the point. The story is talking about things that would surpass human understanding multiple times over.
I don't think we're meant to fully understand why the voices in the darkness stopped him. Just that, as they said, Jaewan would cease to exist as a person if he chose that road. And that it's not a fate one would want.
At the same time, what came after was likely kept vague intentionally to do a big reveal in the next chapter.
I do wonder why he was made to wait for likely trillions of years after rejecting that realization though. Felt a bit pointless at that point, after having already waited hundreds of millions of years.
Ouroboros
it's like
i understand
but i don't understand
then i understand
until i don't understand