The US does not officially consider Taiwan a sovereign nation so China doesn’t throw a tantrum, but in every other way it treats it like one.

This sounds like you’re downplaying the lack of US recognition. I’m not sure what tantrum you’re imagining, but if it’s for the sake of trade relations I don’t think it’s worth being complicit in denying sovereignty.

I agree in principle, but the only thing that keeps China from invading Taiwan is the ability of Taiwan to defend itself (with international help). Explicit US (or broader world) recognition of the ROC doesn't mean China wouldn't invade anyway. Hell even if China would officially recognize the ROC as legitimate, that wouldn't mean they wouldn't invade in the future (they have no problem ignoring past treaties when it suits their interests). This is all just a political game by China to present a narrative that bends reality to pretend they're not invading and taking over a country that neither threatens them or wants to be ruled by them. So while I agree with you it's pretty disgraceful of the US and other countries to advantage themselves through trade and cooperation with Taiwan without officially recognizing their sovereignty, I still think the most important would be if more countries at least supported them in their defense against Chinese aggression.

Exactly. The US _does_ recognize the ROC as the legitimate government of Taiwan it just chooses not to _say_ so. Considering trade, tourism, and immigration policies, it's quite clear that the US treats the ROC as a more legitimate government of Taiwan than it does the PRC of China.

The US does recognize the governing authorities in Taiwan and maintains diplomatic relations with them. https://en.wikipedia.org/wiki/Taiwan_Relations_Act

The TRA provides for recognition of Taiwan, but explicitly not for diplomatic relations at the full Ambassador/Embassy level. Instead of an Embassy for example, there is a liaison office. You and I might think of it as identical to an Embassy, but its a bit of legal sleight of hand from the 1970s to keep China feel respected and make the Taiwanese feel happy. If you look at official photos of visits you never see the TW or US flags together for example like you would do if, say, a diplomat from the US visited France.

Taiwan feels like one of those cases where a little ambiguity is actually safer for all concerned than a clear position. You ideally want a situation where the mainland can saber rattle occasionally to keep their domestic audience happy and where Taiwan can sometimes make it sound like an independent state, but neither moves down the track any further.

An invasion attempt by China or a unilateral independence motion by Taiwan would be a disaster for all three parties, the Taiwanese, mainland China and the US.

The U.S. doesn’t consider Taiwan as part of China.