Agreed on the US Navy, the French and Italians are right up there with the UK so. The former has a full nuclear triad, a nuclear carrier, nuclear subs. The latter has two active aircraft carriers.

Sure, might be challenging to project that power to the straight of Taiwan, but by no means impossible as part of a coalition force. And especially the French have some vested interesst in the Pacific with their overseas territories.

I did mention the French - they're the "Marine Nationale" in question!

I'm not sure the Italian carriers are relevant for operations in Southeast Asia. Maybe once they get F35Bs, but their Harriers would not fare well against much of anything, and that's assuming they have the ability to operate at such a distance from the Mediterranean in the first place. (Incidentally, what most of the world calls a carrier is not what the USN calls a carrier. STOVL carriers are not really in the same class as CATOBAR carriers!)

The region around Taiwan has the benefit of mutiple, unsinkable, carriers, namely Japan, Taiwan and South Korea. Not sure how far Italy deployed its carriers, that being said the above mentioned countries offers quite a few sophisticated naval bases as well. At the very least Harriers are still good enough for escort duty, if shit hits the fan someone needs to keep shipping lines open. A carrier is great for that, Harriers are great for that.

True so that US carriers, and vessels like the De Gaulle and the British carrier (Elizabeth-class if memory serves well) are different beast than the Italian ones. And the US has quite a few of those.

In the event of a China v. NATO war, I imagine most non-US navies would be involved in preventing merchant ships from trading between China and the rest of the world, and in preventing China from similarly interdicting NATO use of the seas.

China will be hindered by not having any real allies, other than short term allies of convenience (Iran, Eritrea, for example).