Thank you for that link (Zigbee 3.0 to Ethernet bridge/gateway (wired not WiFi) inexpensive DIY project for ZHA - #5 by Hedda)
I was not aware of the existence of that thread.
With the new ITEAD Zigbee EFR32MG21 dongle now on the market, I was just interested if an external antenna can be mounted and it can communicate (via a USB-to-Ethernet adapter) hard-wired to a LAN network.
That would already deliver a substantial performance improvement versus the standard Sonoff Zigbee Bridge.
A 3rd benefit (next to a good external antenna + a wired LAN connection), would be that this set-up with the dongle can be powered directly from the LAN network. There is then no need for a power adapter delivering the 3.3 vdc as needed for most of the shelf Zigbee bridges.
And the whole solution will be very cheap and very stable.