The official help centre says Steam Deck playability is something the team may explore and is not a main focus. That help page retains some pre-release wording, so it does not establish a current Valve verification badge or a guaranteed frame rate. Check the live Steam compatibility information for App 1374490 before buying for Deck.
If you already own the game, update SteamOS and the game, start with the available in-game presets, and change one setting at a time. Test the same busy scene after each change, including text readability and controller menus, then revert changes that make the experience worse. Lowering demanding graphics settings is a troubleshooting option, not a promise of 40 or 60 FPS.
This guide does not recommend downloading MacroO: its claimed author, version and performance results have not been established. Nor is there sufficient evidence here to identify Vulkan as the universal cause of Deck crashes. Verify game files and record the actual error before changing compatibility options.