I've been doing some experimenting recently and have been able to get this to work for full movies and even play them on official hardware.
Here are a couple of examples, if it interests you.
I've not yet purchased Supermedium, but will be soon. Just recently got a Quest 2, and wanted to see what comic readers are available, because I thought it would be pretty cool to be able to read my comics on it. Not sure if there's a specified folder that Supermedium would need them stored in, if I do transfer comics onto my Quest 2 to read them.