AirPlay and subtitle playback on Mac

I’d like to achieve something like this: I want to route VoiceOver from my iPhone to my Mac so that it reads subtitles in the TV app. In other words, I play content in the TV app on my iPhone and mirror everything to my Mac—but in such a way that VoiceOver on the Mac reads the subtitles.
When I use screen mirroring, the screen reader does show up on the Mac, but as soon as I start playing a movie, VoiceOver stops reading anything.
Do you know of any way to force VoiceOver to read those subtitles on the Mac? Or is this simply not possible?