Instead of looking for a fake compressed file, use Patch 1.03 with RPCS3, which unlocks 60 FPS and 4K resolution. That is actual extra quality.
Since God of War III does not exist on PS2, the files labeled with this keyword are almost always one of three things: god of war 3 ps2 iso highly compressed extra quality
Despite the technical downgrades, the core combat loop remains intact. Instead of looking for a fake compressed file, use Patch 1
You have two legitimate options: