I’ve long thought that China would be okay with having North Korea re-unified with the south under a southern government so long as the US backed China on reclaiming Taiwan. Hong Kong was the big test to show that China could reclaim a Western colony without breaking any eggs.
I have not believed the US would fight over Taiwan for at least 30 years.
And, I believe, the people of ROK would be more socialist and more anti-American if DPRK didn’t exist.
So, I think the best outcome (not necessarily the most likely) is Korean unification to a non-aligned, nuke-free Chinese semi-satellite.
This will of course allow the Japan-China question to resurface, just as the Turkish-Arab question and the Western Ukraine-Austria questions are resurfacing.
There is really nothing new under the sun.