It might also mess up the relationship between the CCP and Han ethnicity. There's a pretty strong equivalence drawn between "Chinese citizens" and "Han people"

It might also mess up the relationship between the CCP and Han ethnicity. There's a pretty strong equivalence drawn between "Chinese citizens" and "Han people" (Chinese ethnicity, kind of), to the point where ethnic Han people in foreign countries are called "Overseas Chinese" with the implication that they will return home at some point, or that their primary loyalty is to "China" aka the CCP. While many countries have large ethnic Chinese populations that have existed for a long time, there is no other country where ethnic Chinese people are a majority except for Taiwan. Taiwan's existence therefore kind of ruins the 1:1 relationship between Chinese nationality and ethnicity, which is not good for public harmony.