The irony is in a world war China would likely take over the manufacturing plants the west built in places like Thailand and Vietnam to assist
China in the war effort. Further bolstering their war time production.
Can we even talk about a world war like this in the nuclear era? Wouldn't we all just annihilate each other with nuclear weapons if we had a full fledged war?
The more time Russia spends in Ukraine, the more evidence we get that no, we won't just annihilate each other. We will probably do something more complex.
Invading Thailand and Vietnam would likely lead to a military alliance of them US, Japan, the Philippines, Australia and possibly South Korea. If they just want Taiwan at least for now it seems like a bad idea to get all the other countries to enter the war
Those plants depend on a lot of imports for spare parts and raw materials, even if China took them over tomorrow somehow intact with with the people to operate them, they would be out of commission in a month or so.