>>17953334 (OP)
Japan's war of conquest in Asia began well before Germany's war in Europe, but they avoided attacking European holdings in the Pacific until 1940, by which point Europe was preoccupied with Germany, and Japan had formed an alliance with the Nazis giving them the confidence to aggressively expand through southeast Asia, and eventually attack the United States.
Without German aggression in Europe, and no alliance with Germany, Japan likely would've been a lot more conservative in who it attacked, because Europeans would've been able to divert more resources to fighting them.
I think they still would've moved into southeast Asia, because the US and other countries would still have embargoed Japan for its conquests in mainland Asia, resulting in an energy crisis for Japan, and the only way they could really resolve this would be invading Indonesia and taking control of its vast energy reserves.