Yes, a missle gigafactory is impressive pre war. The USA will remove that single factory within the first weeks of any conflict. China better have large stockpiles if their strategy includes gigafactories.
Again I hope nothing happens. I am quite fond of China, the Chinese people, and historical Chinese culture. The USA made special carveouts to help China industrialize. The USA risked nuclear war with Russia in order to get them to back down against China in 1969. We don't want to be adversaries with China and have demonstrably shown so with fairly large policy choices.
I don't think it's clear that a war would necessarily escalate to attacking industrial targets because there is a kind of MAD at play.
From America's point of view, the problem with escalating the war to industrial targets (which I am sure US military planners realize) is that the US has an Achilles' heel in it's reliance on petrol. Almost all US petrol comes from only 130 domestic plants. If those are disabled, most US supply chains will crumble, including food. No need to disable all the factories when there's no way to transport stuff and workers aren't fed. That weakness might be enough to deter the US from striking Chinese industry.
EVs might be one of the bigger bulwarks the US could pursue toward greater national security.