People with that kind of cultural sensitivity, sincere or otherwise, are never going to succeed in the end in the 21st century, which really is a global village. There's not a nation in existence that cannot claim 'ownership' or 'origin' of some aspect of culture, even if it's a hairstyle, hem style, way of preparing fish or fowl, manner of binding a book, or a bead design. If we all decided to claim rights and ownerships of what we decide we want to claim as belonging to 'us,' there's be literally no time to do anything else or hear about the din.
Lana can use the term kintsugi; it's obviously not a word in her first language of English, and I don't think she's pretending or suggesting that it is. On the contrary, like Joni Mitchell using the word 'Hejira' for the title of her 1976 album, it's a kind of way of honoring another culture and its conceptualizations.