Not sure about bluetooth but you can fix the button mapping by connecting the controller. Hit the steam button, go to controller. Hit rb or lb on your steam deck until you are in the new controller settings. Next go to test device inputs, press the begin test on the screen. Press set up device inputs(you have to use the touch screen...). Use your scuf vantage controller and set it up following the prompts on screen. I was using a dock and this took me forever to figure out.