In terms of strategy that the US would use, I would think other than direct fleet on fleet action which would slightly favor China currently due to proximity of battlefield, it would be the US pressing it's strategic bomber/aerial refuel fleet advantage both stealthy and not to lob stealthed cruise missiles at Chinese landing forces while they are crossing the strait. It won't necessarily stop the Chinese forces, but could potentially exact a bloody toll depending on whether China can achieve local aerial supremacy and push it's AA umbrella much further out.If we take Patchwork's analysis as a given, and we proceed with the assumption (1) that China is now capable of neutralizing the US threat in this theater in the opening phase (and the US isn't even gearing up to effectively defend itself), then the next question is the invasion itself: Does Taiwan even have enough targets to justify a month-long air campaign? Probably not, which means a short+intense air/missile campaign, perhaps lasting a few days. After which, the Taiwanese land forces will have (2) no air cover, no logistical chain, no capacity to maneuver and no C4I to coordinate them i.e. they would be operationally kaput.
Now, if we assume the above 2 conditions are met, the rest is just boring. By the time the PLA makes landfall, the Taiwanese Army will be combat ineffective, without any ability to sustain conventional operations. They will melt away on contact. Plus, the probability of a sustainable insurgency is low, given that Taiwan would be an island under blockade without any resupply, and they are an advanced post-industrial society with a lot to lose.
Given the above, the only relevant dimension now is strategic, economic and geopolitical i.e. US vs China on the global stage. If that dimension is won by China, then the rest is just academic. Taiwan's own capacity to defend itself from China is non-existent. The likely outcome in that event would be that Taiwan accepts reunification without a shot fired, if the US is out of the equation.
p.s. Yes, I know Russia also thought Ukraine would be a walkover. None of that changes the above calculus, as long as the two assumptions hold true.
Not a knockout blow by any means as they can be shot down, but the US would be able to manage barrages of a hundred+ air launched cruise missiles at a time without much difficulty. At that volume even if they weren't all ER-JASSM but tomahawks it would be a headache for isolated ships.
This is a way the US can intervene without a horrendous amount of casualties, well at least while allied forces within range get smothered.