Well, it couldn't have been as none of what happened in this chapter is even in the LNs. This is completely new. The LNs always tell the story from Sakuta's perspective, so getting Shouko's is a brand new take. We obviously know that all of this happened somehow as old Shouko exists and there's a timeline where she grew up, but we know nothing of what happened in there, and what happened to all the other characters like Mai, Kaede, Rio, etc. This is basically new lore, and I'm definitely here for it.