Japan's war with the west was all about China. They needed the raw materials that the west was either not selling to them or that they could less and less afford to pay for. A secondary reason was the war material the west was sending to China, although even before PH much of that supply line had been greatly narrowed due to basically no sea access to China trade for the west, only overland. As had been noted, China was a vast sponge that absorbed most of the IJA and a ton of Japanese war materiel. Had there not been an embargo and had the west not been so supportive of China in many ways, it is possible Japan could have forced some sort of war termination that was immensely favorable to them. Some sort of ending where Japan ruled much of China like they did Korea was a fever dream for fanatics - too much China and too little Japan.