I’m very much in the same situation.
The DIRIGERA will just not join my ha- network using ZBT-2. Not once have I gotten an (i) icon in HA to make gw2 the preferred network.
I’ve tried pretty much everything. What actually made it worse was resetting the HA border router. The HA companion app would never sync the new credentials, even though it claimed to have updated the credentials, and the matter device tried to join a non-existant network.
I had to clear the storage of Play Store Services, which resets Google Pay among other things, and reinstall Google Home as it never announced to the companion app that Matter was available (perhaps clearing storage on Home is enough?).
After clearing Play Store Services etc, I removed DIRIGERA from the IKEA app, turned off the DIRIGERA, and resynced the HA credentails using the companion apps troubleshooting feature. It said to have added the credentials.
Then I was able to add a device to the ha-network.
I turned DIRIGERA back on. Factory reset it, and re-added it to the IKEA app.
Using the HA app I can now still add devices to the ha-network and not the gw2-network. But gw2- will not join the ha-network as another thread here said it would.
The closest I got was sharing the device using Matter from HA and adding it to DIRIGERA that way. There is still two thread networks though.
Just now adding the device (a new IKEA KAJPLATS light) using IKEAs app adds its networks credentials to Android and starts using that instead. I removed the device and added it again using the HA companion app to verify this.
When using the HA companion app to add the device, it was never added to the IKEA app even though Android uses the gw2 network. Not sure if that is a feature or not.
It seems like DIRIGERA won’t add its network/credentials to Android until it’s created its gw2-network, which happens when adding a Matter device using the IKEA app. I then assume that Android prefers Thread v1.4 over v1.3 which HA/ZBT-2 uses. The lack of the ha-network in Androids “Thread networks” menu would somewhat confirm that. Although Android has never shown the ha-network in this list regardless of if gw2 existed or not.
Although I’ve been testing with one Matter-device, re-adding 12 lights, 13 remotes/shortcuts, 3 plugs and recreating 7 scenes - not counting fixing the HA automations - isn’t that fun. So I might just use the gw2-network until HA/ZBT-2 catches up with Thread v1.4 and I can join gw2 to the ha-network.
I’ll Matter-share the devices that HA uses for automations.
Edit:
As @cputoast mentioned in a different thread, turning off the DIRIGERA hub will let Android add the matter device to the ha-network. That’s one way of doing this, not the greatest way…