A new Steam Deck beta update just dropped mostly for new remapping options for mouse actions.
General
Fixed an issue where after playing a game it would require extra B button presses to back out of the game's library page.
Settings->Storage will now display drives that are missing a steam library as format targets.
Steam Input
New Configurator feature "Swap Left with Right": While editing a Controller Configuration, you can Swap the behavior of the Left Stick and the Right Stick, or Left Trackpad and Right Trackpad etc. Highlight the source you want to swap in the "Edit Layout" page, and the "Y" button should appear to allow the swap. This should be handy for "South Paws".
New Mouse Action: "Turn to Face Direction". When activating this, the camera will turn to face the direction you are pushing on the Left Stick (default - Track pads, Dpads and Buttons can also be used). Can be combined with "Reset to Horizon" to produce a behavior similar to Splatoon's camera reset button. Note: Dots per 360 must be calibrated for this to be accurate.
New Mouse Action: "Dots per 360 Calibration". By default this will generate 360 degrees of rotation. You can use this to tune the Dots per 360 value in the Flick Stick / Gyro To Mouse modes. This can also be adjusted to produce perfect 180 turns once the "Dots per 360" value is properly calibrated.
Gyro to Joystick modes now no longer generate haptic events when outside the active range.
Desktop Mode
Fixed a case where the store tab would fail to display any content after maximizing the steam window.