I think it’s a horrible idea to abandon an invasion if a 3rd party interferes. The moment that happens then this no longer becomes a conventional war but a war of attrition and I doubt the US is going to stop after losing a couple hundred jets or a couple dozen warships.
1) It gives Taiwan more time to conscript / train civilians
2) Likely boost morale in Taiwan and result in more resistance
3) Allows the US/Allies/West time to build up their forces
4) The US has the advantage of deciding where to fight and concentrate their forces.
Delays will only result in giving the West time to build up and to launch a huge offensive aganist and possibility into China. I don’t see any mainland industrial assets surviving in a prolong conflict if all China does is sit defensively and hopes the US/allies eventually runs of warplanes and ships. US neocons will never accept surrender as long as Taiwan stands.
As I wrote, whether an invasion of Taiwan is temporarily suspended or not, depends on how much the PLA has already committed troops onto the ground on the island.
However -- and let me be categorically clear -- in event of third party intervention, an invasion cannot successfully happen in a circumstance where the PLA does not have the ability to at least contest air and sea control in the general western pacific region, therefore the first priority will be contesting said air and sea control first.
Put the horse in front of the cart. Don't do it the other way around.
Please consider my words carefully "contesting air and sea control" after the US has carried out an intervention, means a general PLA air, naval and missile operation against US forces in the western pacific to deny their ability to assert air and sea control in the region to the greatest practical extent possible. Pausing a Taiwan invasion to carry out such a mission would certainly not allow the west time to "build up and launch a huge offensive against and possibly into China," because the whole point of such an operation would be to degrade and deny their ability to carry out air and naval operations in the region in general.
The cessation of hostilities after third party intervention has already occurred, on the part of the US will depend on exhausting their capability to wage war, and/or will to wage war.
But the idea that the US will cease hostilities against China if China is able to successfully invade Taiwan and force terms of surrender on Taiwan, is very unlikely to me.
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The alternative of not prioritizing air and sea control in the western pacific after third party intervention, would be to have China to continue and carry out an invasion of Taiwan under circumstances where the US is capable of openly conducting air and naval operations between the first and second island chains, where they will not only be able to conduct strikes against PLAN ships operating around Taiwan (including amphibious assault ships), but also against PLA aircraft operating over Taiwan and against PLA bases on China's coastal provinces in general -- not to mention to conduct strikes against PLA positions in Taiwan itself.
Sure, the PLA will do its best to combat US forces in those areas, but that is exactly the kind of war of attrition the PLA will definitively lose, because the sortie and force generating forces of the US in the region (air bases, carriers, logistics centers) will remain operational.