Tip! Buy a few CC2652P USB adapters with external antenna and flash Zigbee Router firmware. Ex:
https://community.home-assistant.io/t/zigstar-zigbee-coordinators-and-routers/338586
One of the best and cheapest commercial Zigbee Router is otherwise “IKEA Trådfri Signal Repeater”:
https://www.ikea.com/us/en/p/tradfri-signal-repeater-30400407/
https://www.ikea.com/gb/en/p/tradfri-signal-repeater-80424255/
https://www.ikea.com/se/sv/p/tradfri-signalfoerstaerkare-10400408/
Also, check out this guide and discussions for more tips on extending Zigbee range and coverage:
https://community.home-assistant.io/t/advice-on-zigbee-range-extending/175882/
PS: An alternative workaround is to just setup a Raspberry Pi with Zigbee2MQTT in that remote area.