That article seems to suggest that the resemblance is related to the Austronesian migration out of what is today China. But that happened thousands of years ago

That article seems to suggest that the resemblance is related to the Austronesian migration out of what is today China. But that happened thousands of years ago, so it's unlikely that any word remained exactly the same over such a long time. Partially, the similarity is just orthographic: the pronunciation of Mandarin huì is written [xweɪ̯⁵¹] in the international phonetic alphabet, while the IPA transcription of Māori hui is apparently just [hui]. Additionally, both words derive from forms that were even less similar: the Mandarin word is reconstructed to come from Old Chinese /* m-kˤop-s/ or /* ɡoːbs/ https://en.wiktionary.org/wiki/%E6%9C%83#Pronunciation_1 https://en.wiktionary.org/wiki/%E6%9C%83#Pronunciation_1 while the Austronesian Comparative Dictionary relates the Māori term to Proto-Oceanic * pui, referring to a cluster e.g. of fruit: https://www.trussel2.com/acd/acd-s_p.htm#4023 https://www.trussel2.com/acd/acd-s_p.htm#4023