To be honest I am not a fan of "inevitable." I think there are certainly a lot of forces that push history to its outcomes but often the path was not so certain in honest hindsight. And to be fair I am pondering the butterflies in Asia if the Central Powers achieve a stalemate, no outright victory but no clear defeat, no Versailles as we know it. With those caveats I am pondering the same conquest of German possessions and linger tension over it. Germany has no way to confront Japan and I doubt there is much leverage in a stalemate "peace" to get them back. I think Japan gets the Marshall Islands as OTL and this might get bargained over, if Germany gets anything it is likely some cash and an apology note.
Longer term I see Imperial Germany under a more Social Democrat influenced government willing to befriend the KMT and generally destabilize the other European powers in China, possibly building a bridge to the USA in the process, especially if the Japanese pursue conquest. In Asia it was definitely the USA versus Japan, not a certainty, but the sparks in the wind. I am not certain if WNT happens, if not IJN build-up bankrupts Japan or the earthquake derails it, either way one might see the IJA rise up to usurp power. A "what-if" here is how relations between the UK and Japan improve, degrade or stay the course. If the British do not repudiate the treaty with Japan the "Special Relationship" likely takes no root and one sees the USA both more Pacific focused and less fertile as a British ally anytime soon. Perhaps the British supply Persian oil and export other materials, that gets Japan out from under the American thumb and under the British. That will drive a deep wedge into Anglo-American relations.
Thailand and France are primed to fight and if the KMT wins in China over the CPC then I imagine it begins to support the Nationalists in Vietnam sometime in the future. The Dutch might move more towards Germany and Germany might leverage the relationship to get back into Asia, at least arming the DEI forces of the Netherlands, supporting the Dutch stay in control, if not at some point at least gain passage and port visits to return a far east squadron and provoke the Japanese at minimum. One cannot underestimate how the USSR will be exerting influence, provoking revolution and setting everyone after each other.
If Japan still goes at Manchuria then it gets messy. If Japan invades China proper it might lead to at least a war in Asia, at worst it provokes a round two in Europe. Either way I do not see Japan getting out very much differently. Best case for Imperial Japan is to stay in the British camp and pursue trade, edging out colonial powers with Nationalist movements and a genuine Asian trading sphere, once China awakes become its industrial trading partner.
