The right play is to maintain relationships (including arms trading) with multiple major powers - as Canada's PM very deftly pointed out at Davos. Getting closer to China doesn't mean exchanging one master for another - it can and should be a way to increase the alternatives available, without going all the way in the other direction.

> The EU would also have opposed it if the US bought Russian, Chinese or Iranian weaponry.

This is such an implausible counter-factual that I can't even begin to imagine what would have actually happened. Still, I doubt any more than some "public letters" would have been issued, whereas I'm sure that the opposite would have resulted in actual economic pressure from the USA against the EU/NATO country that would have dared, under any administration.

I don't see much sign of the EU becoming a Chinese vassal as in relying on it for defence in return for being told what to do. Trading with China is not the same thing.