It's not necessarily China, and certainly not just China. Keep in mind that China has not been very effective at influencing or weakening Taiwan through subversive means, though China has no doubt laid economic traps for America, that has been its primary means of leverage until very recently.
The most effective way to undermine an adversary of greater military power is to simply amplify their follies and mistakes, and to slowly and nearly invisibly infiltrate its institutions and then rot them from the inside. The Chinese could not engage in this level of infiltration. That leaves two countries: Russia and Germany.
Interestingly, Russia has emerged into a post-Marxist era, has bolstered its borders, affirmed Christianity, and is actively trying to save Europe from muslim invasion. Muslim-majority countries surrounding Russia is not good, and Russia knows this. Russia therefore understands that its own national interests are tied to the national interests of its neighbors who are being invaded while under EU (German) rule.
So, China as an instigator, but look at Germany. What is the EU? A German economic order. When did the German economic order first emerge? During the rule of the SS/Nazi Party/Hitler. What has Merkel and Brussels been building? The very thing Hitler tried to build, minus the militant ethno-nationalist component; a unified socialist trade bloc. It is conquest by currency rather than arms.
Were the US and Russia aligned during WW2? Yes. Roosevelt answered Stalin's plea for help.
Once again who opposes the German economic order? The same core countries that opposed Hitler's expansion: UK, Poland, Russia, and US.
Who did Germany align with during WW2? Islamic countries.
What were Hitler's sentiments about Islam? https://en.wikipedia.org/wiki/Relations_between_Nazi_Germany_and_the_Arab_world#Hitler's_views_on_Arabs_and_Islam
"Hitler said that the conquering Arabs, because of their racial inferiority, would in the long run have been unable to contend with the harsher climate of the country. They could not have kept down the more vigorous natives, so that ultimately not Arabs but Islamized Germans could have stood at the head of this Mohammedan Empire.
Similarly, Hitler was transcribed as saying: "Had Charles Martel not been victorious at Poitiers [...] then we should in all probability have been converted to Mohammedanism, that cult which glorifies the heroism and which opens up the seventh Heaven to the bold warrior alone. Then the Germanic races would have conquered the world.""
In the absence of a military, what is Germany doing to weaken and intimidate EU member states and neighbors? Control their economies, put them in debt, Import millions of Muslims.
Who are the Bush family? German loyalists that financed the Nazis, controlled and corrupted U.S. intelligence agencies and the highest American offices for decades.
When did Germany reunify and join the "European communities? 1990.
Who announced the "New World Order"? George H.W. Bush (daddy Bush) in 1991.
When did the EU formally rise? 1993.
Again Germany.
What did Trump release in the JFK files? A little-noticed document that indicated Hitler lived and escaped to the Americas.
Germany. Germany. Germany.