I so feel you there. I have a couple in the chamber I've been holding off on cause of my inability to get reliable results.
I've been using eternity, which seems to mostly work for video files, I've not quite deciphered the pattern yet... maybe I just need to sing about my family dying in a shuttle crash, then I'll see it.
Mp4s weren't working for me! I couldn't get them to autoplay, not that I managed to get webp format to play on every app/ platform either, but that is the current struggle.
Edit: classic Picard faceplam meme, +5 points to you my friend.