Armed Reunification ... which quite frankly is the only logical outcome of an unresolved civil war. I don't know of an example in world history where an unresolved civil war is resolved via voluntary peaceful annexation. Germany was involuntarily divided and defacto occupied, doesn't count. Taiwan even has the island home advantage, so they will roll the dice on holding out until D-Day at minimum.
China with a double GDP and Hong Kong doing well with the NSL the next decade may convince them for a 1c2s that extends long into the future. I think China failed with HK by not having a NSL and clear red lines written in 1997. I think if something was explicitly provided, one would have a better idea of what the world would be like under the CPC. Convince a country like New Zealand or Canada (via lucrative trade deals or $) to take the ones that do not want to stay.