Ahead of the release of DOOM: The Dark Ages on May 15th, Valve have released an update for SteamOS for Steam Deck to get it to actually run.
Read the full article here: https://www.gamingonlinux.com/2025/05/steamos-3-7-6-preview-for-steam-deck-released-fixing-a-doom-the-dark-ages-launch-issue/