China considers Taiwan and Hong Kong both to be absolute existential to their safety and territorial integrity (as to be honest would every other country in the same position), and the leadership will never budge on the issue, so unless you're ready to start paying in bottlecaps probably not.

>Who, if anyone, should be 'world police'?

In an increasingly pluralistic world multilateralism is much more sensible position than some sort of hegemonic world police.