China as it is today is barely 70 years old since they destroyed their own culture as I understand it. And it's been a rocky 70 years. Other nations leaders may get chinese money but what do normal people get from chinese expansion? Communism and an orwellian police state and social credit score? Mass censorship? Chinese don't have freedom or wealth except for the upper class so they don't even do communism right since I thought the point was for everyone to be equal and get rid of classes. China's salami slicing was going to get noticed and piss everyone off at some point I'm surprised it tool this long. Now china's rise on easy mode is over and they are watched and thwarted far more than before. There is no sign of this trend ending. I think king Xi got to confident and thought nobody would ever stand up to him and now he has an alliance against him he can't beat and is still stuck in the first island chain. I don't think chinese want war for some islands and the ability to take others resources.
China is not proselytizing its governmental system to any other country, so there goes you quip with regards to Communism, an Orwellian Police State, a Social Credit System, and Mass Censorship. Those who believe that China preaches or insist that other countries follow its system of government are only imagining things that are not real.
China doesn't get Communism right (as though that is a bad thing), and that is true certainly since Deng's reforms from 1978 that have lifted many hundreds of millions of people out of absolute poverty, and has brought in much state of the art and modern infrastructure, and a technologically fairly advanced country. There are very few who believe in sticking to the ideology of getting Communist right is a good thing.
China has territorial disputes in the South China Sea, but other countries also have territorial disputes that overlap not just with China's, both others. Malaysia, Vietnam, and the Philippines all have overlapping claims with one another as well. Obviously, little attention is brought to to that because they do not have the power to actively pursue their claims. There are those who are not involved in any of the dispute that take sides against and aim at just one country for obvious reasons.
There has not been any territorial expansionism by China because it is not claiming anything more than what it had long claimed. But expansionism is not limited to just territorial expansion. It is also defined as expansion of influence as through financial and economic power, and also improvement of military power and capability without even deploying military forces, as well as cultural softpower. Are those necessarily a bad thing? Obviously, those will bring about concern, anxiety, resentment, and even fear of others, and they will find reasons to criticize them. Filipino telenovelas, Korean K-Pop, and Bollywood have become very popular globally in the 21st century, there are those who dislike that sort of expansionism.