See this thread here:
The general recommendation today is to buy a Zigbee Coordinator USB radio adapter based on the Silicon Labs EFR32MG21 SoC if you use Home Assistant’s own ZHA integration or instead buy a Zigbee Coordinator USB radio adapter based on the Texas Instruments CC2652P SoC if you use Zigbee2MQTT, (and if you use deCONZ/Phoscon then buy a ConBee II adapter). See example:
and
or
Regardless of which Zigbee Coordinator adapter or radio type and Zigbee gateway solution be sure to read and try to follow this guide for Zigbee interference avoidance and network range/coverage optimization → Zigbee network optimization: a how-to guide for avoiding radio frequency interference + adding Zigbee Router devices (repeaters/extenders) to get a stable Zigbee network mesh with best possible range and coverage by fully utilizing Zigbee mesh networking
Zigbee also uses mesh networking topology, which means that most mains-powered devices are a “Zigbee Router” that can act as a signal repeater and range extended by transmitting data over long distances by passing data messages through the Zigbee network mesh of intermediate devices to reach more distant Zigbee devices. Thus to have a healthy Zigbee network, you need many Zigbee Router devices relatively close to each other in order to achieve good coverage and range.
Any battery-powered device will be a “Zigbee End Device” which means that they do not route/repeat messages and thus does not contribute to routing to help extend the range of the Zigbee network mesh.
If using Zigbee2MQTT is a requirement now then today you really want CC2652P based USB adapter:
https://www.zigbee2mqtt.io/guide/adapters/#recommended
Be sure to update to latest firmware, use long USB extension cable, and connect to USB 2.0 hub/port!
Personally use ITead “Sonoff Zigbee 3.0 USB Dongle Plus” (model “ZBDongle-P”) based on CC2652P: