there is also a geography piece. Iranian missiles have to traverse thousands of km of airspace that are under US/Israeli control, with various air based and ground based AD and sensors along the way. in the case of Taiwan, air space beyond the eastern coast of the island are all likely under PLAAF control. PLA rockets also have to travel much shorter distances, from various angles. in fact, geography works against Taiwan offensively too, where it intends to hit any of the larger cities (Beijing, Shanghai, Shenzhen etc), its missiles also must travel long distances under intense PLA AA fire.
Yes.
The other thing to remember is that since the Middle East erupted, I think the likelihood of a Taiwan war has dropped to near zero.
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After the Pelosi episode, when the US actually had to face the prospect of an actual war, I suspect that US hardliners looked at the situation and even they balked at what a US-China war would actually mean.
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But let's take a hypothetical scenario where China believes a war with the US is inevitable, perhaps due to the US supporting Taiwan's formal independence.
The rational course of action is for China pre-empt this by actively a support a proxy war or directly intervene against Israel due to:
1. Israel's deliberate mass starvation (definitely a war crime and arguably a genocide) of 2 million people in Gaza, which has been under Israel Army military occupation for over 50 years
2. The 50+ year military occupation of the West Bank by the Israel Army, which is supporting 500,000 Jewish colonists trying to take control of the West Bank from the 3 million existing Palestinian inhabitants
My guess is that such objectives would enjoy broad support around the world. Remember that the latest polls show that even in the USA, 55% of Americans disapprove of what Israel is doing in Gaza.
If the US supports Israel, then they become the "bad guys" in the eyes of a majority of the world, and puts China on the side of the "good guys". If the US and China are in conflict in the Middle East, everyone will be asking why, which shines a huge spotlight on Israel as a nasty imperialist colonial state.
From a military perspective, it also means the US Navy escorting cargo ships to Israel. They would have to run a missile blockade, similar to how the US Navy has to enter deep into China's A2AD zone to resupply Taiwan. It would be very costly and bleed the US military.
My best guess is that Israel would end up with its electricity grid destroyed and under maritime blockade, with incoming cargo ships under missile attack for weeks/months/years.
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This sort of scenario should be obvious enough to both US and Chinese decision-makers, and they both would have a huge interest in preventing this from happening.