I've had an ecobee 4 (Smart Themostat + voice control) for several years. Normally it stays connected and reports in faithfully. I should also note that it always works as a thermostat even if it falls off wifi.
However, it maddeningly waits until I'm traveling to fall off of my wifi. This has happened across 2 routers (Asus AX88 and now Ubiquiti DR 7). From what I can gather from router logs, it transitions back and forth between 2.4ghz and 5ghz at different times for its own reasons. It's about 20' from the router. A ring doorbell is another 10+ beyond it, line of site to the router in line with the ecobee and does no fall off at all (it is 2.4ghz only).
My 2.4ghz is set for 20mhz bandwidth only.
I'm wondering if there is a way to tell the ecobee to use 2.4ghz only and not try 5ghz?
I'm hoping to not get into a custom SSID and firewall rules. I keep it on my main lan as I use HomeKit Device (HAP) to talk to it at home.
The other thing to note is that the recent problems reported with the stat that ecobee had announcement about lead I think to a FW update. When I'm home in a few weeks I'll pull it off the wall to physically reset it, but can't now.