Since the failed update, my Arc and Sub Mini disconnected and I was not able to sync them again, not even factory resetting both and trying to add everything back from scratch.

Today, I disabled the password security on my router leaving the WiFi open. Reset the Arc and Sub Mini, register the devices in the app and they connected.

Leaving WiFi with no authentication method is not advised, but I’m not too concerned about it at this time until Sonos cares to fix the mess that they did.

Just putting this workaround out there,  hope this helps someone.