Blaming the current situation on the actions of China is beyond bizarre.
What they did was aggressively reduce demand by accelerating the switch to EV's and firing up a few more coal powerstations.
In terms of influencing the midterms - I suspect China isn't anywhere near the front of the queue in hoping Trump get's a beating given the chaos he is causing.
Complaining about foreign interference is ironically straight from the Hillary playbook.
How much of their strategy is to change elections vs other concerns I don't know.
On the other hand the world might be better off if he was more constrained post mid-terms.
Frankly, in terms of countries wanting Trump to take a beating in the mid-terms, I'd put countries like Canada and most of Europe way ahead of China there.
And in terms of China's energy strategy - China is the worlds biggest net importer of crude therefore China's strategy is going to be focussed on managing that first and foremost.
I think it's the US who hoped that the oil crisis would impact China much more - this is the US making, not China.