I think most of it comes down to China;
Japanese Policy in China was intrinsically self defeating. Gain access to markets and gain influence by installing pro-Japanese leaders, sure. Killing Chinese People in wanton savagery and refusing to negotiate with Chiang?
What are the Chinese people getting out of this?
Indeed, why wouldn't the Chinese just fight to the better end to get them out?
Victory for Japan is possible but means that their military advantage over China can be turned into a more advantageous peace for them. I don't have a huge opinion of Chiang--I suspect that given how the Nationalists promptly lost the Civil War against the Communists, it may very well be possible for China to simply splinter. But if there is no other choice, the Chinese people will fight as opposed to getting debased by vicious sorts that are literally using biological weapons against them.
Japan has no chance of beating anyone except China. They didn't have the foresight to win the peace there, although I give them some odds of Chiang collapsing, and some chance that some of their puppet regimes could eventually become decent enough that the Chinese people simply give up resisting their rule.
In all likelihood: They'll go broke before they break the Chinese people.
If Japan tries the Soviet Union, the whole scenario is whether shutting down Vladivostok to US Aid and likely drawing Soviet forces away from Europe [or even a hastily signed concession in the Far East--what's a few hundred miles of icepack if the cost is Moscow?] somehow tips the war in favor of Hitler. The Soviets were crushing in 1945 against the Kwangtung Army, and equally capable in small skirmishes fought in the late 1930s. Japan can only win if the Soviets are truly screwed in Europe, and it's not within their power to decide.
If Japan tries the DEI / British, they're picking a fight with Winston Churchill. This man does not give up, he does not graciously admit defeat, and he does not accept a diminished future. They'll need to fight to the point that the UK sacks him, and that's not going to happen unless Australia or India are simply coming apart. Slim to none, and Slim is a gifted British General.
==========
I think it's very possible for Japan to win in China, if there were a better vision what what winning meant and how to sell it to the Chinese people. Ultimately, though, the situation never really moved before naked force and without giving the Chinese people a good spot in this new future.
Victory: >1%.
Stalemate: Leads to defeat via humiliating economic collapse.