This arc is very deep, as deep as the Abyss.
But so deep that i gave up to reach it, so it is more like a total mess to me, and a "meaningless mess".
The main characters are being pushed by the events from one side to another without any major devenlopment. This arc is like that western series where the protagonists get involved in particular events of a local place, help the local protagonists, find a conclusion, and then leave it as nothing had happened to them at all.
What has Riko learned? That a weird abyss community really cares about subjective "things of value".
What has Nanachi learned? That she was able to sacrifice Mitty again, for the sake of both again.
What has Regu learned? That he already was in that place before, somehow.
The rest is self devenlopment of the Narehate characters, until all be destroyed.
Well, i hope this arc ends soon, in the next chapter, and they become able to move to the 7th layer, which will be even more insane, since i'm pretty sure that it will involve time distortion.
And then i pray for the author, for his health in this current real world cataclysm, and since any new movie or TV series will be produced in the next years, for his concentration and inspiration while elaborating the climax of the story.
The best for all of us, see you next month.