It would have to be a D Day scale, and would have to cross more water.
When they arrived they would be greeted by a million rifles.
They don’t have the means. If they did, they would have done it already.
Not really, it needn’t be a D-Day fleet with liberty ships, LSTs, landing craft, and shore bombardment etc. They’ll use subterfuge against the Taiwan government, isolate them with bribery in our government, and they are extremely capable of moving across and overwhelming the defenses.
And when Taiwan knows the USA is not coming to their defense, the capitulation will come quickly.
It will look very different than D-Day. And the defenses Taiwan has will be too busy with Chinese shooters to stop a mass fleet of small craft. It would start with an unbelievable rain of missiles. The Taiwanese air force will be gone in a matter of hours.
It will be a new model hybrid. Politically take the USAA out of the fight, weaken the Taiwanese government in some creative ways, find an excuse, then just do it.
A nice time to do it would be when America is stricken by a crushing currency collapse, (which they help engineer).