automatically selecting performance preset for SteamDeck

src/logic-scenes/main menu/video_settings.gd

@@ -131,6 +131,14 @@ func load_settings():
 		for key in parsed.keys():
 			set(key, parsed[key])
 	
+	else:
+		if Steam.isSteamRunningOnSteamDeck():
+			_on_performance_preset_pressed()
+			_on_confirm_button_pressed()
+		else:
+			_on_balanced_preset_pressed()
+			_on_confirm_button_pressed()
+
 func propagate_settings():
 	fullscreen_selector.select(window_mode_to_select_id(window_mode))
 	scale_selector.value = render_scale