I agree. No plausible axis victory would actually have them control all of Russia/China and (hence) be toe-to-toe. The most likely axis win would require:
For Germany:
- Gain/retain dominance in the Med
- Take Egypt
- Defeat Russia and seize Moscow, Leningrad, and the Caucuses.
This drives the Russians from the war and forces the UK to accept peace.
For Japan:
- Doesn't try to conquer all of China. Controls the cost without pissing off the Chinese too much (i.e. no Nanking). So, then the Communists and Nationalists fight it out without Japan tying down so many troops.
- Wins at Coral Sea and Midway, making it a much tougher climb to build up for another big fight.
- With UK out, the US agrees to peace with some Japanese contentions.
So, Germany and Japan would still have remnants of China and/or Russia between them and still have the UK and US to worry about before thinking about fighting each other. Perhaps, Germany presses through the Middle East and Germany/Japan both attack India. They could eventually come into conflict there I guess.
This requires at least a 10 year lay over after the end of WW2. Hitler did not have the resources to conquer past Moscow, let alone the Urals, let alone Siberia, etc.
So, what you would need for the Germans to get that far is for them to have had politically subjugated the SIberian successor state to the USSR with a puppet government that would allow them access. Then, the Germans could attack through Manchuria.
The German navy will never be able to take on the ROyal or US navies, so it would be a Germanic Mongol-like empire that would stretch across the Eurasian continent. However, just how far Hitler can stretch 70 million people in this situation would be mind boggling.