I use the GNResound Smart 3D app to control my hearing aids, and it provides a WatchOS version of the app that can be used as a complication in a watch face. The complication icon is the shape of an over-the-ear hearing aid. I've set this up and it works when pressed but the icon itself is only visible during periods of the display being in Always On state. When I raise my wrist or do anything to return the display to normal, the complication icon disappears, although if you press the location the app will run.