So in your case, the network is managed by the Apple devices, not HA. I don’t know enough about this, but I would look into migrating everything to a network managed by HA. I think that’s what this thread explains.
Alternatively, there may be a way outside of HA to extract the TLV data for the Apple network. Looks like it’s maybe not 100% straight-forward, but there do seem to be some solutions.
Also, I’ve seen mentions that the credentials for the Thread network from Apple devices are synced to the keychain on MacOS devices. So if you have one of those, you might find it in your keychain as com.apple.thread.network.credentials.