Exactly. Which is the fine line the West is threading right now. It will be an easy escalation: NATO launches a missile from Poland against a Russian Plane doing a sortie in Ukraine but only to have it get hit when it's flying back in Russian Airspace. Putin has to respond then, he has no choice.
Anyway, I don't know if you can call it a World War if China sits it out. It would just be Russia vs. NATO which is a losing battle for Russia across the board. China's plan isn't to compete with the US Military Globally until 2050, they are more concerned now with exerting their force in their regional area (South China Sea), before taking the next step. I believe they want a formidable "Blue Water Navy" by 2035 (those who know better can fact check this). It doesn't seem logical for them to jump in damn near 3 decades before they think they are ready.
China missed out on the Imperial Age.
they were out there trotting the globe with and amazing navy while Columbus was but China wasn't scooping up colonies.
China was just...China's fleet of Treasure Ships, did you know about this?
for better or worse China got played in the colonial age and now they are trying to come back with monetary militarism, soft power and control of the narrative.
that's allot to juggle.
China needs to stop trying to build islands before it tries to build a navy that can even spit at ours.