I see an argument, probably best expressed here, that there could be more than one territory.

The map is not the terrain, but maybe the map for level 1 is the terrain for level 2.

What exactly does this mean? In some sense it is true: "(approximation of approximation) of reality" is "approximation of (approximation of reality)". You can build a high-level map based on low-level map; it will not be perfect, but since no map is perfect, this should not be a problem.

But the difference between "map" and "territory" is more than just "less precise" vs "more precise". The territory is, by definition, always correct. Maps are imprecise, but they can be improved (usually at the cost of greater complexity). By making better maps we can make our predictions of experiments more precise. And the experiments happen on the reality level, not on the lower-map level.

So if we have a territory and a map, we can improve our predictions by improving the map. But if we have a territory and a map1, and a map2 which is based on map1, there is some difference between the territory and map1... and no matter how much we improve map2 (if we only improve map2 with regard to map1, not the territory), we cannot fix this difference. Even if map2 would model map1 perfectly, our predictions would still sometimes fail experimentally if map1 is imperfect.

If we taboo the words, then "map" is a mental model, and "territory" is a hypothetical cause of all experimental results. (The only way a map could become a territory is if we do thought experiments; but if these contradict with the real experiments, then they are wrong.)

For example we could have a molecule-level model of the world, and an organism-level model of the world. We can explain a lot of how organisms function by how their cells chemically interact, etc. But there still remains an experimental fact that radioactivity can kill living organisms. Radioactivity is a part of territory that is not included in the molecular level, but can leak to a higher level. This is why it would be wrong to call the molecule-level map a territory.