Hello! Just to verify, did you go through the Garmin Connect app to change the units? If so, could you provide a screenshot of this setting being set and the reading the watch shows you?
When you are in the Garmin app, you go to Garmin Devices where you will see Lily and you select it then it will take you to another screen. Go into the general tab there and change the measurement units. Hard to find but it does work!!