I have just got the Galaxy Watch 3, love it apart from a small problem.
I have installed the Samsung app and configured it all and the watch has a 4G plan which costs £5 a month. I was under the impression that when the watch is away from the phone I could call and text with the same number as my phone. When out of range it just asks if I want to connect via Bluetooth.
I have hard reset the watch, and configured it as a stand alone device with it's own 4G connection, but this is for the number allocated to the watch which I don't want. Once configured like this, the watch does have an active 4G connection.
So in short, when configured via Bluetooth to my phone it all works perfectly with notifications etc, once out of Bluetooth range can't call/text etc.
It's paired to a Sony Xperia 3 under Android version 10.
Thank you!