I still have faith that there's something more interesting going on with the boxes, even though journals/notes make sense.
- Selebus has been building up the boxes for a long time, including teasing them repeatedly in every recent update. I can't see him doing a "reveal" where we never see a box and the only thing we're told about the contents is that Ayane didn't learn a single useful/interesting thing from them.
- The alt timeline Maya says that she keeps her notes in the basement, but Maya Prime always had Sensei deliver the boxes to one particular room on the third floor, which we still have never seen inside of. The room has to be important somehow.
To digress a bit, I'm a bit annoyed by Ayane's timeline because it just feels kind of pointless. Sel effectively brings Maya Prime back from the dead and then doesn't have her say or do anything interesting. We learn she keeps notes, but they're useless. Maya and Ayane spend a lot of time talking about their feelings for each other, but that was just putting into words what was effectively shown by their interactions in Chapter 3; and in the end, Ayane forgets everything, so it's not like her own understanding of their relationship progressed at all. They conspicuously don't talk about anything actually important - is it really plausible that Ayane never asks Maya how she resets the world? How about anything about Maya's past - she gives Ayane the scarf to gain New Maya's trust, but wouldn't information be a lot more effective?