I haven't looked too much into thread/matter, but my understanding of them has been basically this: https://xkcd.com/927/
I shudder at the idea of ipv6 addresses for my lightbulbs.
I shudder at the idea of ipv6 addresses for my lightbulbs.
I've always found that the most reliable combination is the Manufacturers app + hub + IoT devices (for example all Aqara or all Nest or all Hue) and interop hasn't worked great because there are special features that only work with the app made for the device (which again, only works with that manufacturers hub) so thread should fix that by making the hub just a dumb Zigbee to IPv6 adapter.
This means that the standard has failed to be an actual Standard, and thread/matter really is a big mess.