Getting time a value changed -OpenHab3

I have roughly 10 remote nodes in my house running on radios. To check that they are opertaing OK, they each send the radio signal strength back every 2 minutes. I would like to display the radio strength and the time that the last message was received. In Openhab2 I did this usinga rule which created a tag - see code below. Is there an easier way to do this in openhab3?. I have tried to make something like work in OpenHab3, but am struggling.

rule Radio22
  Item Radio_2202 received update
  time_change_22.postUpdate( Radio_2202.state.toString + " dB @  " + now.toString("HH:mm") +" on "+ now.toString("dd/MM/yyyy"))

You can do much the same thing in OH3 - but the Datetime handling in rules is different,you’d need something different to format instead of now.toString("HH:mm")

Alternatively, use a timestamp profile to automatically update an Item