The only body that makes decisions about Taiwan is the Taiwanese government. It has 100% control of the land within its borders.
Not sure how much more sovereign you can get than that.
Being that the Taiwanese government claims Beijing and Shanghai as being within its borders, I don't think that this is the case.
It’s a sovereign state with claims over a larger territory than it controls.
The only body that makes decisions about Taiwan is the Taiwanese government. It has 100% control of the land within its borders.
Not sure how much more sovereign you can get than that.