alt Hacker NewsI don't quite understand the benefit of the setup. If there are legacy IoT devices that need unique named 2.4G network, just broadcast another SSID for them. So each router broadcasts main 5G (common name, fast roam etc), main 2.4G (same as above) and legacy IoT 2.4G (with a different name for each AP, and possibly worse encryption and maybe even TKIP). That wouldn't hold back the network for legacy devices.
I run a single ssid dual band network ... what tends to happen is 5Ghz is effectively ignored. 2.4Ghz has better coverage, so everything wants to live there. At least wifi 6 brought improved encoding to 2.4Ghz.
I haven't had luck with the roaming extensions; when I run them, some of my devices won't connect or won't stay connected and it's a pain to monitor. I guess I could run a different SSID with roaming enhancement, but effort.