When I add the sensor I am not able set correct gearing to 1x12. It doesn't let me to set only 1 chainring nor 12speed cassette.
I would suggest selecting a front chain ring where the outer ring matches what you have on your 1X or create a custom chain ring set with both rings being the same size.
What build do you have on the unit?
I see 3 Gear Presets for 12 speed