Iran is under severe
sanctions, half of their oil revenue is down due to them, country had to enforce capital flow and import restrictions to prevent hard currency leaving Iran as their own rial is loosing value. That's economic warfare.
Also it wouldn't take much to break China with soft power means. All you have to do is persuade the constant stream of foreign investors to stop what they are doing-to loose confidence in investing. If you couple that with some good old fashioned blockade of Mallacca straits....
China would try to tank it through with forex reserves but when it runs out.....whole banking system would crash
(it is probably not so healthy as we are made to believe anyway).
On the other hand, pentagon did an assesment of China using US debt as a
weapon, they found out it would not work so well because there are no other attractive options.