I think this is a false dichotomy between benevolence and China secretly plotting and puppeteering everything to some grand self serving scheme. Reality is probably a lot simpler and has little to do with either. In China there's intense domestic competition in most industries, including LLMs.
Going open weights is an easy way to gain mindshare in this sort of environment, which is exactly why Meta also went open weight. The difference is that in China you had leading models going open weight which puts a lot of downward pressure on other orgs to do the exact same. I doubt China's grand vision extends beyond achieving the best system possible, and fostering a highly competitive environment is exactly how you achieve that.
The fact that open weight frontier models may also cause the investment bubble in the US to burst is likely incidental. AI funding is a bubble, and it's going to burst. The exact final cause is again mostly just incidental. The economic damage this will cause in the US will also cause substantial downstream damage to China as well, and they generally aren't so big on the whole punch yourself in the face because you don't like another country, that has become trendy in the West. So the idea of a secret economic attack doesn't even make much sense. In the status quo China wins, so they don't even have any motivation to cause chaos.