Battery powered z-wave rocker remote

There aren’t any exactly like that. The two closest would be the Cooper zwave in the rectangular “decorator” style, the RF 9575:

The Cooper switch that you linked to is the same device but in their “designer” style, which has the curve.

Or the Lutron pico, Although if you use the official SmartThings/Lutron integration, the Picos are invisible to SmartThings, so they can only be used as a virtual three-way with the Lutron Caseta master switch.

There are a number of other battery powered devices, some designed for wallmount, which work well with SmartThings, but they have very different form factors from a traditional rocker switch: