I think HBO Max is weird in that you have to pick the options before you start the movie. I found I couldn't change languages from the audio track or subtitles options while the movie was playing. But I can 100% confirm that I watched all of the movies on HBO Max in Japanese audio with English subtitles. AppleTV 4K.
The only way I can find to switch the audio track is by clicking the word 'English' on the description page (screenshot above), before hitting 'play'. This is really confusing because:
1. There's an option to change the language track once you're playing the movie, but it doesn't show the other option.
2. When you click that button, there's a helpful notification saying you can choose language in 'settings' (which isn't the case!).
3. The icon next to where it says 'ENGLISH' looks like a speech bubble, which to me indicates 'subtitles'.
4. I have to click the word 'ENGLISH' to switch to Japanese!
Ah yes, I remember doing this dance at the beginning of January. As you've discovered, there are about two dozen UX violations with this procedure. Thankfully, I only had to do this once; all the rest of the films played in Japanese by default from then on.
