Here is why a standalone isn't readily available on sites like YouTube or random MP3 databases:
: The movie is available in several regions (such as Luxembourg and Ireland) with English (United States) Audio and subtitles. You can buy or rent it directly from the Apple TV Store . Who Am I Movie English Audio Track Download
If you have a video file and have found a separate audio track (e.g., from a secondary source), you can use media players like to play them together. Here is why a standalone isn't readily available
If you find a separate audio file, you can play it synchronously with your video file in VLC by selecting "Play another media synchronously" in the "Open File" advanced options ⚠️ A Note on Safety from a secondary source)