I mean, I feel like "generally satsified but for a couple of sovreign states" is handwaving things a bit.

Russia similarly feels Ukraine was split off due to "external interference". Makes the claim no more legitimate.

But also see https://en.wikipedia.org/wiki/Chinese_imperialism

So just give or take 35 million people, with Taiwan being integral to the world's chip manufacturing industry, and HK conquest violating the handover treaty. That's far from nothing.

There's a lot of areas that it feels were split off due to external influence. Arguably nearly the whole of east Asia has at some point or another been under some form of Chinese control. They are making extensive claims on the south china sea into waters contested with Vietnam and the Philippines. There are several small islands between Taiwan and Japan which are China claims (and more importantly the oil beneath them). There are a number of territorial disputes with India and Bhutan over control of parts of the Tibetan Plateau which are critical to the water supplies of nearly the whole of Asia. Additionally several border disputes previously settled between China and it's neighbors, such as Russia and the states of Central Asia, are likely to be reconsidered as Russian influence in the region diminishes.

China has also been proactively setting up claims to various exclaves around the world, primarily in the Indian Ocean and Africa. They've set up various "debt traps" where they lend money to build infrastructure like ports to nations that have no serious chance at repaying the loans, and should they default then China receives control. Additionally China is pursuing traditional overseas military bases in Burma, Cuba, Equatorial Guinea, Pakistan, Seychelles, Sri Lanka, Tajikistan, Tanzania, and the UAE, in addition to bases it already has in Djibouti and Cambodia. Such bases are not in and of themselves expansionist, and probably are more about keeping vital trade links open, but increased ability to project power would be a pre-requisite for any expansionist goals in those regions.