I remember someone a bit before theorizing that with each timeline iteration, people lose their factual memories, but retain their emotional memories or whatever, which could explain why our relationship with the girls is so intense and picks up pretty quick, and that for instance Nancy is turned on by the MC from the moment she sees us because she still has all those emotions accumulated from the previous iterations swimming around in her head.
Adding to that thought, people in game also say pretty often that the MC is really smart, and he counters by saying no he just has a good memory. But I suppose maybe instead of having a good memory, he's just well-practiced at this timeline by now, and has retained some deeper memory of the previous iterations. That might also work with the MC pretty explicitly not really remembering much of his childhood in Kredon, at least at first. If when the timeline resets, it resets to after or close to when he moves away to the UK, then he'd only be well-practiced at the stuff from after he moved, and wouldn't remember Kredon as well.
The original theorizer said the MC's knowledge of Dalia's favorite movie despite her never mentioning it, and how he says he already understands the girls pretty well, could possibly be explained by people retaining their emotional memory after a timeline reset. But I think it might come down more to just going through these iterations so many times that one's soul just has to accumulate some form of memory, akin to muscle memory. We accumulate soul memory, or something. Hmm.
On a totally unrelated note, I got further in my replaying, and the MC said to Dalia on the way to Boone's cabin in the cowboy server:
If I were to wake up tomorrow inside a Matrix pod, surrounded by tubes connected to me, I'd probably just nod and say “Oh, well, that actually makes sense, yeah”.
I know there are those who've theorized that the MC we see throughout the game could actually be a projection akin to how everyone else uses their neural implants to project into Eternum, and that his real body is actually somewhere else. I've definitely had the thought myself. I remember at some point we have a vision of Idriel where we're chained up and trapped along with her, and I remember when I first saw it feeling like it might actually be where the MC's true body is, kept alongside Idriel, possibly powering the Eternum system in some way.
But anyways, I wonder if this quote by him to Dalia could be foreshadowing of such a thing. Or, it could just be that Caribdis added it in just to tease and play around with the loreheads like me. I could see it going either way, honestly. But it's intriguing nonetheless.