The onboard Homey zigbee driver is very limited. As you noticed, it doesn’t support dual dimmer devices.
What you can try: Install the Tuya Zigbee test version app (because Candeo probably is a Tuya whitelabel).
Next, follow this link: https://tools.developer.homey.app/tools/zigbee
and interview the device here; Lucky: the app recognises the dual dimmer Unlucky: if it makes no difference, you’d request for support for this particular device as explained here:
Lucky: the app recognises the dual dimmer
Unlucky: if it makes no difference, you’d request for support for this particular device as explained here: