This is what I did for mine
Left shoulder + Z trigger is load state
Left shoulder + Right shoulder is save state
Left shoulder + C up is the menu
input_device = "SWITCH CO.,LTD. Controller (Dinput)"
input_driver = "udev"
input_vendor_id = "9571"
input_product_id = "1397"
input_r_y_minus_btn = "9"
input_r_y_minus_btn_label = "C Top"
input_menu_toggle_btn = "9"
input_l_btn = "4"
input_l_btn_label = "Left Shoulder"
input_enable_hotkey_btn = "4"
input_r_y_plus_btn = "0"
input_r_y_plus_btn_label = "C Bottom"
input_up_btn = "h0up"
input_up_btn_label = "D-Pad Up"
input_left_btn = "h0left"
input_left_btn_label = "D-Pad Left"
input_state_slot_decrease_btn = "h0left"
input_r_x_minus_btn = "3"
input_r_x_minus_btn_label = "C Left"
input_l_y_plus_axis = "+1"
input_l_y_plus_axis_label = "Analog Down"
input_l_x_plus_axis = "+0"
input_l_x_plus_axis_label = "Analog Right"
input_right_btn = "h0right"
input_right_btn_label = "D-Pad Right"
input_state_slot_increase_btn = "h0right"
input_l2_btn = "6"
input_l2_btn_label = "Z Trigger"
input_load_state_btn = "6"
input_l_x_minus_axis = "-0"
input_l_x_minus_axis_label = "Analog Left"
input_r_x_plus_btn = "8"
input_r_x_plus_btn_label = "C Right"
input_r_btn = "5"
input_r_btn_label = "Right Shoulder"
input_save_state_btn = "5"
input_l_y_minus_axis = "-1"
input_l_y_minus_axis_label = "Analog Up"
input_down_btn = "h0down"
input_down_btn_label = "D-Pad Down"
input_start_btn = "12"
input_start_btn_label = "Start"
input_exit_emulator_btn = "12"
input_b_btn = "2"
input_a_btn = "1"