For better or worse no one's wading into that clusterfuck in the name of civil rights, and no one outside the US has the force projection capacity to even consider it. Maybe we'll see some economic sanctions, but from an ideological perspective the CCP cannot and will not allow Hong Kong to leave China, it would invalidate a cornerstone of their existence (their ability to keep China united, a very rare historical anomaly).
Historical revisionism much? China was prepared to come and take Hong Kong, the only thing that preserved the current state was a deal that allowed China to save face. The U.K. had no ability to defend Hong Kong - they actually got a much better deal than could have been expected, with China worrying about its international reputation at the time. The Chinese could have walked right in to Hong Kong and taken it much, much more quickly.
As it happens, there has been a Chinese government-in-exile in Taiwan since 1949. Its practical influence on the governance of China itself since then has been zero to two decimal places, and is unlikely to increase in the future.
I am not at all sanguine about China's oligarchy, either for Hong Kong or the world, but geopolitical fantasies are just a way of avoiding facing the facts.
https://twitter.com/nomsolence/status/1237906111837040642
The 1:20 clip I posted is the final summary, but the entire 20 minutes is worth watching.