China only has fewer aircraft carriers compared to the US, but its destroyer/cruiser number and nuclear submarine numbers are getting closer and set to surpass the US within a decade.
The latest estimates for the size of the Chinese People’s Liberation Army Navy’s nuclear powered submarine fleet indicate that it has overtaken that of the Russian Navy in size, making it the second…
militarywatchmagazine.com
In the meantime, the US lacks the hypersonic capability of China.
China sure can protect Iran from the US invasion, but the problem is that Iran doesn't like China nor they fully trust China, same for China.