ESL here, not Chinese. I find meticulous to be a perfectly normal word, I think I don't really use it, but I think I read it from time to time, but maybe I just read some sort of publication by a fan of the word? :)
Same for surpass and boast, I think I use "surpass expectations" and I had to think for a moment, I would use 'brag' these days but pretty sure in school I learned boast, which sounds more formal BE to me, but of course I'm just guessing here.
They're all perfectly normal words that literate people use. The problem is the typical American struggles to read beyond a fifth grade level and is actively hostile toward more advanced vocabulary, as the country is deeply anti-intellectual overall.
ChatGPT, of course, behaves like its training set...and the majority of that set is professional writers' published works, which would be more likely to use words like that. It's a collision of academic and literary writing styles with the expectations of people who think Harry Potter or the New York Times (which specifically targets a fifth grade level, placing them above other papers) are challenging reads.
Maybe I skimmed the article and didn't look for specifics enough, because I did not see a bias towards any level of education. But of course I am biased myself, probably using all the fancy words and still making grammatical errors like a fifth grader, and iirc I did not have a native American coworker (aka people with whom I regularly talk and not just write) for 10 years, only other ESLs and some British people.
Same for surpass and boast, I think I use "surpass expectations" and I had to think for a moment, I would use 'brag' these days but pretty sure in school I learned boast, which sounds more formal BE to me, but of course I'm just guessing here.