Hello everyone ! I'm struggling with this today so I'm asking you for help (I already looked on the subreddit but didn't find anything)

I got movies on my smartphone, mkv type, and I just wanna cast them on my mi box s. VLC is offering something for this, and it's working great but not for the subtitles. So I tried multiple applications Nova video player, web video cast, etc. But for one application, the sound is not working (but the subtitles work), and for another one it's the reverse, sometimes both won't work. I'm sure it could work with both because every app make at least one thing, but I'm looking for an app who could do everything 😅

Thanks a lot for any help, I'm french btw sorry for any English mistakes.