Hmm quite a lot of [aubergine / shower emoji copyright TheElementsOdeToJoy] being talked about China on here. China does not want to undermine the EU, Xi said that the brexit (or whatever Cummings is calling it now) vote was a failure of stable government, proof democracy doesn't work. It wants the EU in place as another power block between America, Russia and themselves. It also wanted the UK in the EU so that it could access European financial markets through the city of London, for instance for trading the RMB. Since passporting seems now to be likely to be [emoji / shower emoji] away by Cummings (because why would he want to support mainstream ethicalish financial services companies who contribute taxation revenue over complete shysters like his hedge fund mates who don't) they are now looking at alternative strategies.
The EU never stopped Britain trading with China. Germany does more trade with China than the UK, it wasn't the EU that was holding the UK back. The only reason that there isn't a EU / China trade deal is because the EU refused to allow the Chinese to continue unequal trading practises like flooding the market with cheap steel which protected the British economy.
China is not in a good position to take over the world economy, too many internal strains even before Coronavirus (which my money is on them containing as they did SARs now they have faced up to the problem, ironically because now being an even more authoritarian regime they can put millions into quarantine as they put millions of Uighur's into camps). However Xi has all his work cut out continuing to deliver prosperity and lifestyle to his middle classes and stopping the gap between them and the rural poor, many of whom are migrants to cities, becoming a political pressure point. That is what happened in Xinjiang, neutralising a rural source of dissent. But did he?
The Belt and Road initiative is designed to support that internal project, cementing economic stability through infrastructure ties. He knows better than to overreach himself into destabilising expansionism. Even his military strategy, the nuclear arsenal, the South China Sea islands is defensive. He could spend more on sabre rattling but he hasn't.
China should have imploded decades ago by any model of economic or political development. People have predicted both that and world domination but neither has happened. But Xi claims the mandate of a Confucian sage emperor and so far his and his predecessors strategies have been all about achieving stability. That is why he presents himself to the west as champion of liberal free trade and to his people as an authoritarian hard man. He will continue playing all sides against each other in the name of stability.