Apex Legends was one of the big things that they were using as an example to show off the Steam Deck and is one of the main games listed on their "Steam Deck Verified" pages. I assume this means that Valve and Respawn/EA were talking to each other about it at least.

I would like to see Steam to require games to not ban Linux users for using Linux (or at least disclose that they are doing it) as a requirement for being listed on their store, but that's probably not going to happen.