Check: Getting started | Zigbee2MQTT
and: [APP][PRO] Zigbee2MQTT
That is a good place to start.
A separate Zigbee dongle is connected to a NAS, RPi or other.
The devices are connected to this dongle and “imported” in Homey via Zigbee2MQTT App for Homey | Homey
No, they just increase the Zigbee range evt, as they act as ordinary routers, like for example (almost) any light bulb or outlet.
