Neither, and I fail to see the difference between them. Neither country would do such a thing with altruistic goals and both have proven they shouldn't be trusted. We have already seen how badly the US fucks up other place's economies and governments with their meddling.
You fail to see a difference between a country run by an autocratic cult of personality and a country run by a democracy? That’s troubling. The US commitment to human rights is flawed, but it’s nothing compared to the dystopia that is China. Values matter.
Being a democracy didn't stop the US from killing Guatemalans over the possibility of bananas costing a couple more cents, or installing or supporting dictatorships in foreign countries when it benefited them. How much power do voters really have in determining foreign policy or large financial decisions?
It is also not quite right to treat the Chinese government as a single minded monolith in determining their own policies. There is tons of internal factions and divisions within their own political system. Yeah sure certainly Xi has a lot of power, but only so long as he doesn't try to buck off the opinions and ideals over the rest of their political class, a political class who holds many of the same opinions and ideas as the US political class. The political sphere in China today is nothing near what it was 50 years ago.