The S21 is a surprisingly comprehensive package, with Lemfo having equipped it with an LTE modem, GPS and a heart rate monitor, among other features. The S21 supposedly runs Android 10.0 and can access the Google Play Store too, for better or worse.
https://www.notebookcheck.net/Lemfo-S21-A-budget-smartwatch-with-GPS-and-LTE-for-US-79-99.519538.0.html