Warhorse Studios gave us a pretty good look at Kingdom Come: Deliverance running on the Steam Deck handheld in a recent video on YouTube.
"Kingdom Come: Deliverance is a story-driven open-world RPG that immerses you in an epic adventure in the Holy Roman Empire. Avenge your parents' death as you battle invading forces, go on game-changing quests, and make influential choices."
Sadly, this is a game that was supposed to offer up native Linux support years ago as a result of the Kickstarter crowdfunding campaign. When the release was coming up, the developer cancelled both Linux and macOS support for launch and then just never ported it. A huge shame but at least with Steam Play Proton around there is another option to play Windows versions on Linux through Steam.
ICYMI: check out some things we learned about the Steam Deck recently.