[wolvoleo]

Samsung had this reverse charging from the phone but they also dropped that function with the watch 7 :(

Having said that I did use it but it was terribly slow and both the phone and watch heated up too much. And the positioning was very finicky. A whole charge would last 3-4 hours where the official charger is 30-40 minutes.

Power banks with watch charging also exist and cheap aftermarket charging pucks. Not as fast as the included one but not bad.