Just answering your question "What I still don't get is what could China possibly want with Taiwan?".
If you don't believe the rational I sketched, informed by analyses such as that by the Council of Foreign Relations[1], you can also learn more by reading directly from China's Mission in the EU about the China One principle: http://eu.china-mission.gov.cn/eng/more/20220812Taiwan/20220...
Are you trying to evaluate their intelligence or predict their actions? I for one agree that attacking Taiwan is strategic folly. That doesn't mean they won't do it. Invading Ukraine was strategic folly too. The CCP are smarter than Putin, but not immune to mistakes. And again, look at their built strategy.
If you don't believe the rational I sketched, informed by analyses such as that by the Council of Foreign Relations[1], you can also learn more by reading directly from China's Mission in the EU about the China One principle: http://eu.china-mission.gov.cn/eng/more/20220812Taiwan/20220...
[1] https://www.cfr.org/backgrounder/china-taiwan-relations-tens...