It is easy to explain conceptually, but for a lot of people to believe it, they would need to read a full TL. I have thought about writing the TL, and I might in the future. But to get away from Japanese biases, lets use what the US Army official assessment was in late 1941. If you want to read, it is available on online. I will try to do a brief outline, and it may be easier to see what he Japanese THOUGHT would happen. Please avoid ASB garbage, because beliefs not reality drives human actions.
1) By January 1942, the Germans hold Moscow and Volga river. Russia is cutoff from oil, supplies from Persia. Leningrad starved to death, literally. Murmansk and other Northern routes have been cutoff. German has achieved victory and now switches the majority of its resources west.
2) February 1942, German begins to occupy French West Africa. It takes six weeks and it is uneventful. The Med is totally shut to all Merchant traffic. Presumably Malta and Gibraltar are conquered/neutralize, but the reports don't cover this item. Starting at the Equator, a naval war begins. All Allied convoys must stay outside of bomber range of West Africa. U-boat pens are built in Africa, and the U-boats have more time on station. Now people like to scream ASB, but this is what the US Army official intelligence appraisal indicates is likely to happen.
3) Now lets get back to Japan. For simplicity sake, lets say the battles go much like OTL through March 42. Japan likely does better because the Allies will have pulled out resources compared to OTL, but lets skip the benefit, because it does not impact the negotiations too much.
4) The carriers in the Pacific will be desperately need to fight in the Middle Atlantic against German airpower in West Africa. Germany likely has begun making naval projects a higher priority, and Western Intel has detected it. Doolittle raid is cancel. I know this is a call, but it decisions have to be made in ATL's. Japan sets back and begins to fortify. So does the Allies, but with substantially fewer forces than OTL.
5) Japan makes a peace offer to the USA. Wake comes back. Philippines will be allow independence but no military (Think Belgiumish). Some concessions thrown UK way such as Thailand is allowed to be neutral again, some symbolic payments for Singapore and Hong Kong.
Now in this scenario, where FDR is facing a war in Europe that will last at least a decade, he has a tough choice. Fight a war much like OTL, but slower with Japan. Or make a counter peace offer. As losses pile up, and if there are additional major defeats, the Japanese offer becomes more tempting. And since the war is going slower, Truman will also have a chance to accept a peace offer or make one of his own. Or whoever the next president happens to be.
It is key to remember that a Germany who defeats the Soviets puts a lot more pressure on the RN and USN. It is not that German wins at sea, or even come close. It is that the larger the battle front, the more naval units will be needed. The higher % of the German war economy focused on the UK means more naval units will be needed. Even if the USA does not send any carrier or battleships to the South Atlantic, the cruisers, submarines and destroyers sent will have a noticeable impact. And IMO, the counter West African fleet/army will have at least one carrier, 1 battleships, and 4 land divisions that would have been used in the Pacific in OTL. And likely much more. The Germans will be initially weak in West African and there is a lot of merit in early and aggressive counter invasions by the USA at major ports and bases. Since the Germans have room to retreat, it likely ties up the divisions used for years. The Naval units will be largely sent to the Pacific once the ports are secured, but this might be a year or two later than OTL.