China is much larger and more diversified than you seem to be giving them credit.
Net trade globally, they're running an imbalance of 1.5-2% GDP.
They're growing at almost 7%/year. So there's quite a ways to go to get to -2.8.
If gdp growth stagnates, there's a very real risk that the Chinese housing bubble will collapse and bring down the entire economy with it.
But that doesn't result in a recession in China. They're growing at 7%, about the same as exports to the US. From that 7% subtract imports from the US (which would also be cuttoff and replaced by Chinese companies), and imports for export (which don't produce value for China)... and the result is that an end to US-China trade does not produce a recession for China.. they would still be growing by a few percent (note, the US economy only grows at 2-3%).
So they'll still have a growing economy... and they're still moving people from the rural areas into cities. So it's not clear to me that this collapses the housing bubble there. Possible though? Sure, maybe.
Meaning, if all trade between US and China was cut off tomorrow, they would only lose 7% of GDP. So how do you get from that to 5X?
Seems like you have a model of the Chinese economy from a decade ago. Fact is, China is much larger now, and much less dependent on trade today.
Also keep in mind, a good portion of our imports from China consist of items that were imported into china for assembly. Look at all the items from other countries inside an iphone... yet when an iphone is assembled in China, the value gets assigned to China. If you adjust for this, it significantly reduces (but nowhere near eliminates) the trade imbalance. So the numbers above, actually overstate the impact on China's economy from cutting off trade.
Edit: corrected a few of my numbers from worldbank data