Right now the only obvious enemy is China.
Not only do they have enough people, they have a huge imbalance in the male:female ratio. Excess unmarried men are a societal risk. Additionally, the population hasn't fully appreciated that their life savings have been squandered building ghost cities that will never be occupied. That won't go over well as their boomers attempt to retire. Even without that, their demographics are terrible because their Baby Boomer generation was huge and the one-child policy created a much larger generational imbalance between the boomers and millennials than exists in the rest of the world. Last I saw the revised population estimates were 200-300 million fewer Chinese than we thought 10 years ago. Shrinking population = shrinking economy = social unrest.
You know of a better way for a dictatorship to quell social unrest (with a bunch of excess males) than war?
We're already in the early phases with the trade war. Think of it from their perspective, not ours. The US is forcing a reindustrialization in the West, which is a direct attack on China's wealth generation. And the primary pressure points against America (rare earths production being a huge one) are being identified and, at least rhetorically, mitigated in future plans.
If we allow China to take over their half of the planet, particularly all the east Asian countries, then maybe there's no war. But we won't, so eventually everything will spill over into another global conflict.
Honestly I'm amazed at how many people just operate on the assumption that humanity has evolved out of wars.