China needs room for its people more than it needs a market for its stuff.
Selling us stuff is just the means to get financial backing for their military expansion.
With us out of the question politically China could be the military aggressor they’ve wanted to be for the past 60+ years.
There is much closer and easier territory for China to take than the USA. New Zealand, for example, is a low-hanging apple ready to be plucked anytime. Borneo, the Philippines and lots of other places would be invaded before the USA. For that matter, they could simply colonize Africa much more easily than invading a down but still dangerous USA. A China invasion is about #300 on my worry list.