The US has already been doing that, of course. They'll do whatever they can regardless of China's posturing. Though material engagements do absolutely have costs, so actually participating in a resistance movement is far from nothing. At the same time it does align more or less perfectly with their massive industrial capacity. The key is to choose the right battles, e.g. Palestine, where participation is does not translate into, "China is going to fund revolutionaries in my country so I'll prop up these right wing paramilitaries and get even more US bases", as would definitely happen in India or The Philippines. Leading the charge on Palestine would probably improve China's international position. Even just in their neighborhood this would be very popular in Malaysia and Indonesia.
Of course, this is just expressing a frustration from a Western person in the imperial core. We should remind ourselves that when thinking about the possibility for even better outcomes by states controlled by communist parties, we are literally in the states fighting to ensure the imperialist system and the genocide of Palestine. We should spend most of our time thinking about how to position ourselves to best fight that system and that genocide, not nag about states for not doing enough.