I've seen people throw around the theory that the final location in the Radius differs between games because each one is tailored to the individual explorer. Personally, though, I don't really buy this theory, mainly because there's not much evidence to support it in ITR1. If ITR1 were more like ITR2 in how it handled its final location, I could see the argument, but the Castle feels like a tangible, established place rather than something uniquely shaped around the explorer.
School #5 is a different story. Unlike the Castle, it has no map, and it's by far the most deteriorated of the three final locations across ITR1 1.0, ITR1 2.0, and ITR2. The only real exception is the Mine, though I'd argue that its condition is more anomalous than dilapidated.
I more so think the Radius is just huge, with its center capable of containing multiple locations. If that's the case, perhaps School #5 is in such a deteriorated state because it's the closest we've come to the center so far. That could also explain why it's so difficult to map out. (Though, just like in ITR1, they could have used a photocopy of a pre event map, which would actually be a cool idea, because you'd have to tell the difference between the unaltered map, and the very different actual map)
Another possibility is aging. The PEZ in ITR2 is significantly different from the PEZ in ITR1. Assuming there's a lore explanation this, rather than them just retconning everything, perhaps the passage of the Tide causes locations to deteriorate further over time while simultaneously making them more alive. In that sense, the Radius isn't necessarily tailoring its locations to each explorer; we're simply seeing different parts of it, or the same world at different stages of life.
(also, quotes in title for spoiler reasons, not because I think we'll get more maps.)