Dude, surely you understand how modern trade works. The USA stops selling stuff to China? China just pays more for food from third parties. Other countries will be outbid by China, and so they will find another provider for their food (which will very possibly be the USA, seeing as the USA will have all that food lying around it's not selling to China). Basically, this is lots of disruption, lower availability of some types of food, additional cost etc. but let's not pretend China's going to run out of food.
Where do you think China might be able to readily source coal, oil and gas from? As a hint, you literally just mentioned the USSR.
Weapons are irrelevant unless someone's actually shooting. They make the military fanboys cream their pants, but they're not that big a deal. This is a trade war, and what matters is who is least able to tolerate economic pain.
And my point is that it is increasingly likely that the USA would fold first. Partly, I suspect, because Americans just aren't used to doing without, and they will make life intolerable for their leaders first. A lot because China makes just so much of the material products that the USA's economy depends on - including its much vaunted tech sector.
You want to say that the USA owns the tech? You mean it owns
the intellectual property. Much of the stuff then made from that IP is made in China. If push really comes to shove, China just ignores US patents, then it's got both the tech and the factories. LOL!