This fairly anecdotal, but LLMs aren’t that good at translating Japanese. From what I’ve seen they are pretty good with many other languages, but they really struggle with Japanese → English translations, possibly because the languages are so very different. I have yet to see a machine translation of more than a couple paragraphs of native content that didn’t make huge mistakes on the nuances. A lot of times there isn’t even a straightforward translation from Japanese to English. The first example that comes to mind is the “Watashi… Watakushi? Boku? Ore?” from Your Name, which, using a direct translation, just means “I… I? I? I?”.

The first song is 片目のウィリー, the second song is ロックンロールは鳴り止まないっ.