Going along this the thing about Chika, we also see Chinami in the event. Does that me she was also subject to 19 years of that? I don’t think so, because that wasn’t our Chinami, in my opinion, as she acted nothing like the one we know. It seems to me the entire thing is more metaphysical than materially physical, like a dream that feels like years pass, but in reality only a few minutes actually pass.
Dreams are weird like that, and given the gods ability to manipulate minds and experiences to make you believe one thing or another, I highly doubt it was literal.
Now, that does NOT mean Chika won’t think it was real or literal, especially given her lack of knowledge about the world around her, so I wonder if she’ll remember it, and if she does, will SHE think it was real or not?