2020. Endless
King Elbas had made it clear that the sky had to come before everything else, and Noah couldn't go against that, especially after accepting that his companions were becoming too heavy to bear at his current level. Both of them required energy that only the white layer could provide, so they had to prioritize that mission to fix their existence.
However, Heaven and Earth had a point. Noah felt relatively sure that they had spoken the truth, meaning that the monster outside the sky could become a great problem for everyone.
The non-world was also interesting. Noah had seen how powerful the non-existence could be, so the superior realm could only bring steep improvements. It might have even solved the natural weakness that afflicted that empty creature.