I'm in the UK so only had access to the s3 Frontier Watch that connects to my phone to allow calls.
However dependant on where you live if the watch is available a person can add a line to their contract which costs a set amount per month like a normal contract does however I think it may mean a different mobile number is attached to the watch.
I'd suggest to call your mobile network operator to enquire if they can provide this service.
Current Phone ~
Samsung Note 20 Ultra 5G SM-9820 _256Gb SnapDragon 865+
Samsung One Ui 2.5/ Android 10.