The given URL is a local one. You can open it in your network only.
RWL021 works with ZHA and Zigbee2MQTT in Home Assistant. It’s well supported there.
Cube OS hasn’t officially confirmed support for RWL021, but if you’re using one of the compatible dongles, the remote might work, though it could require manual setup.
and how to do “manual setup” on Cube OS?
As of now, Cube OS does not include native support for ZHA or Zigbee2MQTT. Instead, it uses its own Zigbee integration layer, which is still evolving. Cube OS has its own Zigbee stack, designed to work with specific coordinators like SONOFF ZBDongle-E/P.
In short — abandon hope for now.