[thaumasiotes]

Something similar that confuses me is the recent shift from calling the river "Yangtze" in English to calling it "Yangzi".

Yangzi is the correct pinyin spelling of the syllables that "Yangtze" was meant to indicate. (Similarly, if you want to spell them in modern pinyin, you'd have Laozi instead of Lao Tzu/Tze, Sunzi instead of Sun Tzu, and of course Kongzi instead of Confucius.) But the Chinese name of the river is something completely different. What's the point of updating the spelling of the English name as if it were also the Chinese name?