Honestly, I don’t know what China has to gain from taking Taiwan by force versus what they can gain much more cheaply by just befriending and trading with it.

They could arrange an on-paper reunification. The key is to choose your words carefully to avoid upsetting anyone and give as much lip service as possible to Beijing while giving many of the “real” benefits to Taipei.

• The Republic of China is dissolved. The government in Taipei will continue and is renamed to just “Taiwan”. All legal documents will be issued under the name “Taiwan”. Former officials of the Republic of China continue in office as officials of Taiwan. The leader of the Taiwanese people is the president of Taiwan (台湾总统) and the administrative organs that govern their portion of Greater China (大中华) is the Government of Taiwan (台湾政府). Other than that, the status quo is acceptable and shall continue indefinitely.
• Taiwan acknowledges it is a part of Greater China (大中华) and that Taiwanese people are members of the Chinese nation (中华民族). Note that the Chinese terms used here refer to the cultural idea of “China” and not the country.
• In international affairs, all instances of “Chinese Taipei” (中华台北) are replaced with “Chinese Taiwan” (中华台湾). Note the use of the cultural “Chinese” rather than “Chinese” referring to that which relates the People’s Republic of China. All mainland publications will adopt the Xinhua News Agency’s style guide recommendation of referring to Taiwan as merely “Taiwan” rather than “Taiwan Province” (台湾省).
• The People’s Republic of China recognises that Taiwanese people have a right to self-government and disclaims all rights of government (政权) to the people of Taiwan. Taiwan does the same to the mainland. Sovereignty (主权) is held collectively by the Chinese cultural nation (中华民族) as a whole and cannot be exercised unilaterally, but the respective governments have the right to defend the Chinese nation’s sovereignty on their respective territories against external threats.
• Taiwan’s right to build up its military for the purposes of deterring external threats is recognised. Taiwan and China agree that their respective militaries will not be used against each other. Each military defends its own side of the strait and neither is obligated to help the other in any conflict whatsoever.
• The Taiwanese people will decide when they would like the adopt the socialist system. There is no deadline for this to occur. The mainland respects the right of the Taiwanese people to choose and will not force the matter nor will it interfere in the internal politics of Taiwan.
• Taiwan agrees to publicly support Beijing’s claims in the South China Sea, agrees that such region belongs to the Chinese nation, and disclaims all interests whatsoever beyond 22 km from its coast (note: equivalent distance to a country’s territorial waters). The portion of the exclusive economic zone of China east of the island Taiwan and west into the centre of the Taiwan Strait is reserved for the sole use and benefit of the Taiwanese people. Anything more than 22 km south of Cape Eluanbi is disclaimed by Taiwan and for the exclusive use and benefit of the mainland. Taiwan is not obligated to use its naval forces to enforce any claims laid to portions of China’s EEZ not reserved for it.
• The People’s Republic of China will respect the Taiwanese government’s ability to interact with foreign nations even if such interacts disagree with the way mainlanders choose to relate with that nation. To that end, the PRC will support Taiwan’s participation in international organisations as a member non-state entity. If such a designation is not allowed by the organisation’s rules then Taiwan will apply as a state but never style itself as such once admitted, always referring to its delegations as representing “Chinese Taiwan” (中华台湾).