gotta be deck compatible right?

Probably not fully, unless they actually do work on the games. The cutscenes on some of the games play with a proprietary protocol that even Proton-GE can’t run. So, while the game works, the cutscenes don’t.

It’s feasible that they will fix it, but I consider it highly unlikely.

Do you have any documentation on this you can link because it doesn't really make sense what you mean and I love learning about these things. Most of the cutscenes will be rendered in engine so nothing special there, and the pre-rendered ones if they used an unusual codec I don't get why the codec isn't baked into the game files which would render that also a moot problem.