For China it would have made more sense long term to first "incorporate" Taiwan into their country and only after that start turning the screws on both Taiwan and Hong Kong.
And I do not think Taiwan will become Gaza if China eventually attacks - unlike Israel, China has quite a lot of enemies in the West.
PRC doesn't have any capable enemies in the west, including US, that can prevent PRC from turning TW into a Gaza. Which PRC can do with purely mainland based fires at this point. The force balance is too lopsided off PRC shores now. PRC's fleet of PL191 can basically level all of Taiwan urban areas in a few months, weeks considering other munition stockpiles. They can build a few hundred more chasis and frankyl TW->Gaza would take a couple weeks. Otherwise every inch of TW is within a few minute strikes from mainland, so resupply is out of question. There's nothing preventing TW from becoming Gaza except Xi is kind of nice bro.
To your narrow point of view focused on military destruction - there are other ways the West will counter a Chinese attack on Taiwan.
If China does attack Taiwan, China will be the second biggest loser.
There really aren't anything substantial, nothing the west can sustain anymore let alone in 5/10 years or 2049. It may very well be PRC is poised to be the least biggest loser, aka relative winner. IMO we're in stage where the longer PRC waits and accumulates the harder they win and frankly there's shit all west is able to do about it (on procurement side over next 10-20 years) with gap extending in PRC favor.
Plus a lot of morals go out of the window when there is a real threat and a lot on the line. Even between the new tensions with China and Japan, the US appears to be quiet: https://www.ft.com/content/bf8b5def-db4d-43ac-91cf-bea5fcfa3...
This is definitely not the sort of "protection" I would rely on.
PRC sees the writing on the wall and, being the pragmatic bunch that they are, will probably not invade Taiwan. Unless Xi really controls the country 100% (this I do not know since I am not a Chinese observer) and goes crazy like Putin did.
I don't think Ukraine can win with the way things are going unless the West joins the fighting or Russia collapses. Waiting until Russia collapses will quite possibly be a long time which will result in a Pyrrhic victory for Ukraine. They will have an entire generation of dead men at the rate things are going.
Invadin Taiwan would have a huge negative impact in China. Another poster in this thread, in the process of contradicting himself, said that the longer PRC waits the stronger they become. The conclusion then being that the best course of action for China is to never invade Taiwan. I fully subscribe to this conclusion.
Full unification is similar to the Greater East Asian Co-Prosperity Sphere (大東亜共栄圏). The foundation would probably be some ideology centered around the area’s 3000+ years of shared Buddhism and Confucianism, rewarding wealthy multi-lingual business families more than the average person.
Something more realistic and beneficial to you (assuming you are Asian in an English-speaking country) would be world unification .