: Look in /home/deck/.local/share/steam/steamapps/ for two major space-hogs: shadercache : Pre-compiled shaders for games.
: Once installed, open it from the Application Launcher (the Steam Deck icon in the bottom-left corner) under the Utilities category. How to Use the Analyzer to Free Up Space disk usage analyzer steam deck download
If you prefer a different interface, other popular options are available via the Discover Store: How do I find what is taking up SSD space? : r/SteamDeck : Look in /home/deck/