It really isn't, though I suppose you could tendentiously argue it's about keeping the one they have.
Depends how you define Empire.
They are certainly keen on taking back Taiwan, which at the end of the day is objectively revanchist Empire building, no less than Russia invading Ukraine and the situations have quite a lot of similarities really, e.g. the unilateral declaration of kinship. Attempting to annex the entirety of the South China Sea seems like imperialism as well.
We can only speculate on their wider goals, and most likely that they themselves don't know. But I don't think you could say with any certainty that they would stop with Taiwan. It seems self-evident that they feel entitled to be hegemon of Asia, and the "great rejuvenation" essentially refers to returning to hegemon status. In reality a major reason they will never compromise on Taiwan is the same reason they want the South China Sea - they want naval hegemony over the Pacific. By controlling shipping lanes there they can effectively control choke points in global trade and exert control that way.
For what this would look like, you would only have to assume they continue behaving as they currently do, using every piece of economic leverage in their power to exert influence over private companies. At the moment this means things like informally banning imports or "discovering" that something doesn't meet regulations, manipulating social media to create boycotts, or making certain demands in exchange for market access.
If they had total control over shipping in the Pacific, which is what they really want and a big part of why they want Taiwan, I don't see any reason why they wouldn't continue trying to bend countries in the region to their will, but with more tools to do so. They essentially used astroturfed social media and state power to stir up a campaign of harassment against South Korean citizens and businesses in China over the THAAD issue, I don't think they would be shy about naval blockade of the Korean Peninsula or against Japan whenever they felt they need either. The subtle and not-so-subtle attempts to claim that South Korea was culturally a part of China seem to me quite possibly deliberate attempts to get people used to the idea that Korea belongs to China. Here is some background for people who aren't familiar with this:
[Newsmaker] SBS cancels ‘Joseon Exorcist’ after historical controversy
I don't think you can say with any certainty that they aren't interested in Empire building. I think that the nature of the Chinese political system is inherently prone to expanding its power, for reasons that 20th Century critics of totalitarianism have outlined which also quite clearly apply to Xi's China.
Hannah Arendt wrote:
[The method of infallible prediction] is foolproof only after the movements have seized power. Then all debate about the truth or falsity of a totalitarian dictator’s prediction is as weird as arguing with a potential murderer about whether his future victim is dead or alive – since by killing the person in question the murderer can promptly provide proof of the correctness of his statement. The only valid argument under such conditions is promptly to rescue the person whose death is predicted. Before mass leaders seize the power to fit reality to their lies, their propaganda is marked by its extreme contempt for facts as such, for in their opinion fact depends entirely on the power of man who can fabricate it. The assertion that the Moscow subway is the only one in the world is a lie only so long as the Bolsheviks have not the power to destroy all the others. In other words, the method of infallible prediction, more than any other totalitarian propaganda device, betrays its ultimate goal of world conquest, since only in a world completely under his control could the totalitarian ruler possibly realize all his lies and make true all his prophecies.
This is a perfect description of how the Communist Party of China operates. There is no objective truth or not, only 话语权, discourse power. In fact Wang Huning, the main intellectual of the Party,- says in his earlier work that the Communist Party can only survive by controlling all the information outside of China, and I think it is quite obvious that they are taking vigorous steps to achieve this, and that this is an impetus which will makes them strive for maximal expansion of power.
Further, the Communist Party is totalitarian in that it accepts no limits whatsoever to its authority. Before Xi there was pretence at limits, with collective leadership and term limits. But now there are none, and it is not a coincidence that concentration camps re-emerged at the same time as firmer control over censorship and ideology came in, and at the same time as a more aggressive foreign policy, because the concentration camps are much more about the exercise of total power than they are about any political utility per se, this is also why they function as laboratories for social control as they do in Xinjiang today.
This passage from the chapter "Total Domination" (which I have written out here by hand, copied from my physical book as I can't find it online) in Arendt's "Origins of Totalitarianism" I found very haunting and strongly influences how I view the Communist Party of China. I read it after the disappearance of a Uyghur friend of mine who I had learned about the situation in Xinjiang from back on 2015-16 and I sought out Arendt in trying to make sense of it. It still sticks with me a lot and I think it is correct.
If we take totalitarian aspirations seriously and refuse to be misled by the common-sense assertion that they are Utopian and unrealizable, it develops that the society of the dying established in the camps is the only form of society in which it is possible to dominate man entirely. Those who aspire to total domination must liquidate all spontaneity, such as the mere existence of individuality will always engender, and track it down in its most private forms, regardless of how unpolitical and harmless these may seem. Pavlov's dog, the human specimen reduced to the most elementary reactions, the bundle of reactions that behave in exactly the same way, is the model "citizen" of a totalitarian state; and such a citizen can be produced only imperfectly outside of the camps.
The uselessness of the camps, their cynically admitted anti-utility, is only apparent. In reality they are more essential to the preservation of the regime's power than any of its other institutions. Without concentration camps, without the undefined fear they inspire and the very well defined training they offer in totalitarian domination, which can nowhere else be fully tested with all of its radical possibilities, a totalitarian state can neither inspire its nuclear troops with fanaticism nor maintain a whole people in complete apathy.
...
It is in the very nature of totalitarian regimes to demand unlimited power. Such power can be secured if literally all men, without a single exception, are reliably dominated in every aspect of their life. In the realm of foreign affairs new neutral territories must constantly be subjugated, while at home ever-new human groups must be mastered in expanding concentration camps, or, when circumstances require, liquidated to make room for others. The question of opposition is unimportant both in foreign and domestic affairs. Any spontaneously given friendship is from the point of view of totalitarian domination just as dangerous as open hostility, precisely because spontaneity as such, with its incalculability, is the greatest of all obstacles to total domination over man.
...
What makes conviction and opinion of any sort so ridiculous and dangerous under totalitarian conditions is that totalitarian regimes take the greatest pride in having no need of them, or of any human help of any kind. Men insofar as they are more than animal reaction and fulfillment of functions are entirely superfluous to totalitarian regimes. Totalitarianism strives not to despotic rule over men, but towards a system in which men are superfluous. Total power can be achieved and safeguarded only in a world of conditioned reflexes, or marionettes without the slightest trace of spontaneity.
Quite a lot of that passage and other parts of that chapter reminded me a lot of my experiences with the Chinese Communist Party, in particular the contempt for any form of opinion and extreme instrumentalism. I think this is also why some in the Party initially welcomed Trump, because they believed he is a businessman and would deal with them purely in transactional business terms, which is the preferred modus operandi of the totalitarian instrumentalist technocrats, as it amounts to predictable carrot-and-stick reactions. Meanwhile the liberal desire for international friendship with China is generally regarded with contempt, suspicion, or something that can be taken advantage of.
But based on this understanding of the instrumentalist technocratic state seeking constantly to achieve consistency in its propaganda system and viewing all information outside its control as a threat, whilst accepting no restrictions on its power, I think it would be very foolish to underestimate what the CCP are capable of and what their ambitions are.
www.spiegel.de
www.theguardian.com
