My only remaining smart device is an off brand smart bulb on my front porch. It is set up to turn on at 6PM and off at 6AM. It disconnected from my network years ago, but has kept working great nonetheless. I think of it like a Mars probe going about its business. :-)
>>jimmyd+(OP)
When mine disconnected from the network I discovered it was flashing nonstop red, green, and blue. I'm surprised the neighbors didn't come over and complain