China lacks both the ability and the willingness to engage face to US in military conflict outside of East Asia. This is a fact, and acknowledging it doesn't shame me.
And once China were involved, many of US's allies(such as Japan and Australia) would see this as disrupting the balance, they will do everythings they can to against China. It is not good for middle east.
Iranians can protect their country, all China need to do is to make US leader know the more time he wasted in Iran, the economy problem in US will get bigger.
All in all, what they did could not weaken China. This situation is enough to restrain US, making it inclined to avoid committing too much military force.
I'm not saying China is meant to go to war. Turkiye is in NATO, we are on paper allied with the USA and much of Europe. Yet all the major players in that alliance will support our enemies. In the case of Syria the USA and Russia worked together against Turkiye, you could literally see them co-ordinate their military movements together to counter the various Turkish incursions. When Trump basically threatened erdogan with war, but Turkiye went in anyway the americans fled their positions which were protecting the PKK but made sure to hand them over directly to Russian forces instead.
When Turkiye downed a Russian jet, much of Europe actually sided with Russia against their NATO ally pulling away air defences from our border. The EU placed various sanctions and embargoes against us when we moved on Syria etc. I actually think that the russians seeing how cowardly the europeans behaved concerning a strong nation like Turkiye, probably incentivised their invasion of Ukraine expecting the Europeans would act like similar pussies. To be fair most of them did behave that way only to pretend they were on Ukraines side when they saw the Russians were not going to succeed there.
If a country like Turkiye small in size and resources comparatively to China can make it so the entire white man alliance won't get their way entirely, surely Chinese support could have made it so iran could have done much better then they are doing now. Not to mention the maduro fiasco.
Maybe its just a Turkish mindset, but i feel had we been 1.4 billion with your resources, we wouldnt give two shits for what the USA, Russia, or EU wanted. If all of them came together we still wouldnt give two shits for it. We would feel ourselves far too big and far too strong to listen to their bullshit let alone take it.