Steam Deck

 It is recommended that the controller scheme should be set to Official Layout for Baldur's Gate 3 - Gamepad with Joystick Trackpad. It is also recommend the display is set to Aspect Ratio: 16:9 and Display Mode: Fullscreen. You can set this in Options > Video. 

If you are experiencing performance issues on your Steam Deck, please ensure that you are running default video options set to “medium” and that AMD FSR 1.0 is set to balanced. It is also important to check for software updates in system settings so your Steam Deck is up to date, especially any performance or stability updates. 

If installing to a micro SD card, it is recommended that a 256Gb Class 4 micro SD card is used, with high read/write speeds (UHS-I to UHS-III).