Ah, indexed on your “black box” remark and completely missed the lovelace point.
At present, my new Floodlight Nest camera is the only of my 3 cameras that works reliably in Lovelace. My other two (Nest Doorbell - wired), intermittently say “Unavailable” (it’s almost always “unavailable” and rarely shows the stream). Is this a known/widespread issue?
I would probably start a separate thread on that, but mine does show unavailable from time to time I would not call it constant. Usually when it does it is not coming up well on the Nest app even.