Have a look at USB over IP software. Something like VirtualHere. You can trial it with a single device but - auto connect won’t work with the Trial, so you will need to manually connect.
It’s a sonoff basic (acting as power source and wifi bridge) connected to a CC2530.
I used the new zigbee to tasmota module, which depends on the zigbee2mqtt stack and relays on tasmota to bridge to wifi.
There’s a much easier flashing method in this video:
which is for a 2531, however the process is exactly the same for a 2530 except for using the correct zstack and pinout.
The pinout is available in this article:
The main advantae is offcourse portability, but additionaly you dont have to set up additional software in your server as the tasmota bin communicates directly via mqtt.
Depending on wireless or wired connection requirements;
You can go with xiaomi mija zigbee gateway, root it, install openwrt/zigbee2mqtt or attach directly to zha
there are also some methods to hack tuya gateways and use them with same idea.
or you can build one from scratch with raspberry pi and usb stick
All off these would enable to create a secondary zigbee network without extending the initial network range. Please share if you know more options to have network based zigbee gateways
It has 2 modes, bridge mode that allows ZHA to connect directly to zigbee chip over TCP.
I use the other mode where it is a standalone gateway that does all the zigbee stuff and exposes MQTT events, some of the events need some complex rules to to read the various change states. I use node-red to simply that.