Yeah, I downloaded the untranslated japanese version. Audio started working after I applied the MTL patch myself. However, you still need the other patch for missing images and pixel animations.
I usually do that :
- start from raw files from untranslated version
- apply MTL via Translator++ or wait for someone to do it
- replace only data/*.json files and keep original System.json file
I never had any issues with that. I also use RPGMakerMVGame Hook patcher so I can keep the original text in Japanese and copy it to Google Translate, DeepL and Jisho to have a better translation.
One last thing to note is the encoding of the zip. if it comes directly from DMM, use a japanese encoding (Shift-JIS should do the work)