AP212 is a great dark digital watch face for Wear OS based smartwatches (only round smartwatches)

Important note about heart rate measurement & display:
*Heart rate measurement is independent from the Wear OS heart rate application and is taken by the watch face itself. The watch face shows your heart rate at the time of measurement and does not update the Wear OS heart rate app. The heart rate measurement will be different than the measurement taken by stock Wear OS app