China could do what Britain did in the Falklands war, declare an exclusion zone around Taiwan (limited to the EEZ of Taiwan and China) and operate within it. If China attacks US bases in any Asian nation, it would be an article 5 declaration by NATO and mutual defense treaties with Asian nations. But if China operates solely within Taiwan EEZ, repelling attacks, it won’t draw in as many outside forces for some time, which maybe enough time for them to land hundreds of thousands of troops.
The key is a fast and severe opening attack over the first 24-48 hours followed by landing 500,000 troops within the first day (10,000 heavy helicopters, hundreds of large aircraft for paratroopers thousands of landing ships), followed by 200-300,000 troops everyday afterwards for a week; till there are nearly 2 million PLA troops on Taiwan.
The US studied a similar invasion (during WW2; calling for 300,000-400,000 US troops/marines against 30,000 Japanese troops) called operation Causeway if I’m not mistaken. (Referenced at 6:30 in the following video)
Attacking us forces has many pitfalls, as seen with this exercise, but if China operates exclusively on Taiwan it will be calling the US’ bluff. What Ukraine has shown is that, the west will send arms but will try to avoid directly fighting. If China can land 2 million troops in a week on Taiwan; taking mountain locations with helicopters, it will be a fait accompli, and be harder diplomatically to dislodge PLA forces.
P.s. a lot of what China will have to do outside of building up its military is economic. China needs its own economic allies around world. China will need to help “economically rehabilitate” nations like DPRK, and other marginalized nations/non-aligned nations in Asia, Latin America and Africa so they can be productive and able to economically support China in a new world order (with enough collective GDP to be consequential) ; BRI, and promises to develop these countries left behind. These countries also need to have the restrictions that imposed sanctions have placed on them removed or mitigated more comprehensively to be able to be fully developing economies, for their own sake and china’s sake.
An example would be a China port across the Red Sea from Djibouti in Yemen in exchange for promises to help rebuild Yemen. A rebuilt Yemen could be neutral via a vi Saudi Arabia, but maybe more supportive of Chinese logistical needs and open up their economy to Chinese investors once rebuilt as well as hosting facilities to watch the northern side of the Bab- Al Mandab with the Chinese watching the southern side from Djibouti.
A more robustly and independently (independent of the western markets) economically growing China would also be able to work behind the scenes and use coercion to undermine resistance through Taiwanese business community (promises to spare their business in a bombing wave) similar to the Talibans lightening offensive in the summer of 2021.
The Chinese could/would probably use the rhetoric that taking Taiwan is ending the Chinese civil war and the US fought its own civil war when the south tried to secede.