I don't think China can easily occupy over 20 million heavily armed Taiwanese without a long brutal war which would be really bad for world economy. Covid is bad enough. Some years ago China promised peaceful rise, but it canceled one nation, two systems agreement with Hong Kong, incarcerated hundreds of thousands of Uighurs, and has stretched itself with many border disputes and wars.
by all indications, the majority of the people living in taiwan will not put up a fight. when asked if they want independence or be a part of the PRC, they mostly said independence, but when asked whether they will
fight for independence or become a part of the PRC, most said become a part of the PRC. plus if china absolutely had to keep 10 million guards on the island, then they will, if it came down to it. the day the CCP lets taiwan go without a fight is the day the revolution the us keep hoping will happen in china, will actually happen.
polls are no guarantee taiwan was easily roll over, however most polls do leans toward surrender if push comes to shove.
also china did not "cancel" one country two system. HK was having it too lenient for too long leading to a mess of traitors and a generation being taught by china hating Catholics and CIA/NED/MI5 agents(seriously what kind of teachers brings their grade school students to potentially dangerous protests?, the kind employed by the CIA duh.). the national security law is well within china's rights and within all treaty obligations with the british, and it's hypocritical for the british and american to complain since they have over a dozen even more harsh security laws in place right now. no sane government would tolerate what happened in HK.
and overextended? china is winning on like every front. NED/CIA funded riots in HK failed. CIA attempts to funnel terrorists hardened in syria into china from Afghanistan failed and they have now even left the country. india tried to start something when it thought china was wrecked by Covid and couldn't respond, but they got slapped. Relations with the russians are at an all time high. SK is feuding with japan and has kept mostly quiet about china. chinese flights around Taiwan is becoming the norm. AUKUS has irked europe and even many asian countries like Indonesia, meanwhile providing little advantage to the us, since the three are already allies and the nuclear subs are 20 years in the future(not that those would change anything as they will simply be a extension of the us sub force). US trade war on china has been a major failure, Meng Wanzhou is released without any crimes charged against her realized. and day by day china is closer than ever, every single day to overtaking the us in nominal GDP.