Has anyone been successful configuring Shelly 2PM Gen4 as a zigbee extender?

I’ve been trying to extend my zigbee network through the extension capability of Shelly 2PM Gen4, but my Sonoff thermometer snzb-02wd does not see it. It will only connect to my Sonoff dongle, which unfortunately is unreachable where I want to use the thermometer. Has anyone had success extending the zigbee network with the Shelly device?
I verified the Shelly device is configured as a router in the visualization map.

I have 4 Shelly 2PM Gen4 devices set up as rollershutters now, and the visualization graph does show one is extending the network.
Note that this only works if you integrate the Shelly device as Zigbee (I’m using ZHA). It does not work if you integrate through the Shelly integration point, even though the device has been rebooted to use Zigbee.