I played this via Heroic Launcher in desktop mode, docked using a Keyboard and Mouse. Because the steam deck counted as a controller the control schemes would flicker between keyboard and controller controls every time I pressed a button on the keyboard or used the mouse in game. To overcome this issue I had to run death stranding through Steam from the heroic launcher with the "Mouse Only" control scheme, now only keyboard and mouse controls are shown and it's fully playable and great!