I’m confused why electoral systems seems to be at the forefront of your thinking about the relevant pros and cons of US or Chinese domination of the future. Electoral systems do and can matter, but consider that all of the good stuff that happened in Anglo-America happened under first past the post as well, and all the bad stuff that happened elsewhere happened under whatever system they used (the Nazis came to power under proportional representation!).
Consider instead that Trump was elected with over 50% of the popular vote. Perhaps there are more fundamental cultural factors at play than the method used to count ballots.
Yes, my mistake. I meant Trump votes > Harris votes and forgot about 3rd parties. On the other hand 49.8% vs 50% + 1 feels semi trivial when compared to say the UK where Labour received 33.7% of the vote.