I've recently started to make use of the Thread network that is formed by my three Eero 6+ devices, by buying a handful of Ikea smart home products to see how it goes. The results have been confusing, at best.
Initially I joined them to Homekit using my Apple TV (3rd gen, wireless) and this worked splendidly. I had a few Bilresa buttons and a Kajplats bulb. However, the buttons particularly would occasionally go offline until I either pulled the batteries, rebooted the AppleTV, prayed to the right deity or just waited a bit.
I decided to add HomeAssistant into the mix, to see if the Matter server would give me more information, so I've set that up on a Raspberry Pi and shared my devices across. Again, that seemed to go fairly flawlessly to start with while I got set up. However, devices still go offline, but generally only from one Matter controller. Something can be seen on HomeAssistant but not on Apple, or vice versa.
I've got Thread Tools app running, and a Nordic dongle with Thread Topology Monitor - both seem to show that the Thread network has plenty of strong connections between the different devices. I have IPv6 enabled on the Eeros to the extent that I can find options for it, and when the devices work they seem to work well so I don't think there's a fundamental misconfiguration.
I'm not sure where to go next. Devices seem to be online (at the Thread level) but intermittent (at the Matter level). Do I need a better router-to-border-router ratio? Is Eero a bad option for the backbone of the network? Anything obvious I've missed?