China is already harassing and sinking fishing vessels and trying to close the South China Sea. It may soon try to enforce an ADIZ over the SC Sea as well. Not great.
China is a growing aggressive power with cyber attacks across a multitude of countries and is running, like Russia, disinformation campaigns to undermine democracy.
It is in the interest of EU and the US, and indeed many countries, to have a rules-based international order. It is increasingly in the interests of the US as its power is in relative decline.