Hard to predict when China would actually pull through with it but it's inevitable that it would attack. It would not allow Taiwan to remain free. I do saw some vids that for reasons, China have to do this within this decade.
Even without the chip monopoly I doubt the US would take lightly the "reunification" of Taiwan with China. It basically allows China power projection into the Pacific and would compromise US positions there. From hereon nothing stands in the way into America.
Ukraine in NATO on the other hand is just something that would be nice to pester Russia with but something the guys in Washington wouldn't lose sleep over.
Perhaps. These invasions don't exist in vacuum so it's difficult to gauge what sort of things are actually pertinent in the decision making process for the folks in Washington. If it's money at the end of the tunnel, then that might be a good indicator of immediate action. Hong Kong was taken by China without much push back from the U.S. I wouldn't expect them to get militarily involved, for obvious reasons, but hardly any condemnation. Taiwan isn't a Hong Kong, and Taiwan isn't a Ukraine. It might be one an instance of waiting to see what happens because I'm a firm believer that China will make an attempt at Taiwan within the next 10-20 years, if not sooner. We will find out eventually.