I tried to do this for weeks and gave up. It can’t be done how you want it to. The only option is to give the users a list of possible options as your preference and then based on that list (which you know the possible values) use a big If then statement to call the right label.
See this for the thread I posted: Change labels of child device programatically?
And this for a example of code I used. It’s the “Child Contact Sensor” used with the ST_Anything project but modified to be more useful for different types of contacts. I did the same with the Konnected Contact Sensor also: https://github.com/vseven/SmartThings_VSeven/blob/master/devicetypes/vseven/child-contact-sensor.src/child-contact-sensor.groovy