China is very much in the same position the US was in at the turn of the 20th century: lots of territorial conflict with old powers, but a grudging recognition that the winds of change are in their favor. All it will take is a single small-scale conflict akin to the Spanish-American War and China will have unquestioned dominance over the South China Sea (like the US did with the Caribbean and South Pacific).

Their neighbors will be forced to play nice with them or be blockaded. Which is exactly what the US did in the early 1900s with central / south American banana republics. There is a playbook for ascendant superpowers, and China is just playing their best hand. Anyone who isn't a superpower is just going to have to accept what China does.