My first (stand alone) running watch is a Garmin. The Forerunner 235 has a heart rate monitor on the back and connects to my phone for feedback and music control.
I can leave my phone at home and still record my runs. More freedom, more fun.
The excellent garmin connect app on my phone syncs everything to the online portal. With bluetooth LTE it’s always connected (when within 10m) Also the phone app provides access to the Connect IQ store with lots of apps for the watch. I’ve loaded a new watch face and battery meter.