All China cares about is will the oil keep flowing.
If there is a change in the government of Iran it is quiet possible Iranian oil production will eventually go UP.
It is also quite possible it will go down in the sort term.
However, IF the government of Iran becomes more friendly to the world in general that is good for all people.
China may not be able to buy the Iranian oil at a discount to the current market, BUT the production of oil will increase. Eventually bringing down the price.
Iran really does not have ANY friends in the world. They just had countries that would buy their oil IF they sold it cheaper than every one else.
“All China cares about is will the oil keep flowing.”
Defeating the US isn’t on their list? Perhaps they have other plans.