I’m going to let my other thread die since I’ve worked through that issue, posted my issues and how I ended up working around it, but some people didn’t like that, so now that all that’s resolved, need to focus on the remaining issues, which are fully in the migrating OpenZWave to ZWaveJS arena.
The first time I tried to migrate the ZWave network, it did as I originally posted, and migrated the network, but only a portion of my devices were migrated. Possibly because I continued with the migration before all devices were fully polled.
Since then, I had originally just reverted to a pre-migration snapshot, and everything was happy, and I then worked my way through all kinds of trials and tribulations before getting to a ‘happy spot’ running HA 2021.12.10 using Python3.9.5, where I tried it again.
This time it just sits at ‘Loading Migration Data’ with a spinning wheel, and the following shows up in the log:
2022-11-30 22:34:17 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection]  Error handling message: Unknown error
Traceback (most recent call last):
File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/websocket_api/decorators.py", line 27, in _handle_async_response
await func(hass, connection, msg)
File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/zwave_js/api.py", line 248, in async_get_entry_func
await orig_func(hass, connection, msg, entry, client)
File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/zwave_js/api.py", line 371, in websocket_network_status
controller = client.driver.controller
AttributeError: 'NoneType' object has no attribute 'controller'
I had a thought that maybe the reason why it wasn’t working now is that HA ‘writes’ something to the ZWaveJS host that caused the future migration attempts to fail, so I re-imaged my SD card with the original baseline image with the functional ZWaveJS UI installed, but nope. While the rate at which it performed the initial poll does suggest that the reason why my initial attempt partially succeeded - likely the devices that migrated had completed their interviews and the ones that didn’t hadn’t completed their interviews - I’m at a loss as to why the initial attempt partially succeeded, but all subsequent attempts have totally failed, including attempts made from the same instance that initially partially succeeded, but after reverting the machine to the snapshot I took prior to starting the migration the first time.