It is my (only slightly tinfoil) theory that had COVID-19 not escaped a little early China's plan was to arrange a "sorta bad" pandemic in Taiwan alongside their agents causing civil strife. Then the CCP could slide in as peacekeepers with health resources and a vaccine and just........stay.
Shitty lab protocols messed with the plan a little bit, but the Chinese are nothing if not patient.
I don't think they'll straight up invade, as that opens them up to armed conflict with the west. They'll orchestrate some crisis that allows them to swoop in with a veneer of acceptability to the rest of the world, spend 5 or 10 years "helping" out the poor Taiwanese, then there will be an "election" that votes to rejoin the mainland. The west can pay lip service to our treaties, and China get's their lost island and the South China Sea