"Star wars" is feasible with reusable launch to orbit vehicles.
Taiwan does have fairly good stocks of weapons and ammo. It's also great terrain for fighting a defensive guerilla war. It'd be China's roleplay of "Russia in Afghanistan".
Observe that "the world" will not be helping Taiwan. India won't. Russia won't. Brazil won't. Nigeria won't. Pakistan won't. Bangladesh won't. Nigeria won't. You get the drill. US will, and probably Europe too, but why assume that these will 1) be able to defeat China in a conventional war in its own back yard, and 2) will even try to do so?
The democratic countries will come together, the same ones that helped Ukraine; delete from that list authoritarian (democratic or not) countries, and democracies that are led by authoritarian dictator wanna-bes (so if Trump comes back he'd be conflicted, because he loves authoritarian power, but indicated his displeasure with China). Probably not Hungry. Russia doesn't matter if they aren't nuking you. India, there is the authoritarian bent the country it is on - non Hindu people aren't feeling so happy about their country. I'd think India will feel torn because they want to fight Pakistan freely but don't want to increase the power of China. Brazil is another partially fallen democratic country, wonder how that vote will turn out at the end of Oct.
There are two reasons those countries will help Taiwan - because they don't want authoritarian dictators to take over democracies, and because Ukraine reminded us all of the importance of stopping dictators - we can't wait for them to decide they have enough. It's over 80 years since the last time the world went through it, German and Japan were the original threats (with Italy and a few others), now it's China and Russia. The chip making part of Taiwan will all be decimated in the first few hours of a war (you thought that would be one of my reasons to intervene ;-)). It will be re-created bit after bombing it and damage and just losing power it will be hugely weakened, hurting both sides.
Ukraine showed how much more powerful the militaries of the western alliances are. I'm sure China will not be so weak and kleptocratically weakened as Russia was, but they haven't been in battles recently so they will need some ramping up to really organize. I'm sure China will be able to do major damage to navys trying to operate around Taiwan, sink a few us carriers. But the US and the other western countries are about a lot more and they can operate in countries around there.
China is a powerful country, they have brilliant engineers and scientists and that economy and a vast population. They are not to be under-estimated. The world must move forward to promote democracy and stop dictators.
When people don't like to discuss what they call platitudes is because they will not benefit. The US has endless problems, with 200 years or racism, slavery, denial of institutional racism, then our destruction and the big lie about Iraq, and finally Afghanistan had a different situation but still managed to screw that up. My friend who recently moved back to Taiwan to retire will probably also have an interesting viewpoint on such things. "Please don't kill me, China" might describe his views. He thinks (hopes?) there won't be a war because the west will help protect Taiwan.
Practically, PRC can simply mine TW ports, crater run ways, via glide mines and MLRS all within PRC borders (that can hit anywhere in TW + adjacent). US + co doesn't remotely have the demining, sealift or airlift capacity to logistically support TW off PRC waters. Nor will they convince any commercial fleet/insurers to go on suicide mission of... invading One China territory. It's like how Operation Starvation crippled JP during WW2. Except TW is much smaller than JP and PRC is a much larger industrial power than US during wartime. PRC can unilaterally and trivially render TW inaccessible - it can blockade TW with basically zero sustained naval or air effort.
And really if US/JP try to run the blockade they're legally invading Chinese sovereign territory and it's WW3 anyway. TW may have chance to survive a PLA invasion, but IMO no chance of breaking a PRC blockade. Folks are grossly underestimating the proponderous of advantages PRC has near her coast.
Taiwan between missiles and air force elements would be uninvadable. The only way to control Taiwan is to land a quarter million soldiers or more.