@David-TP firmware: 1.1.2 Build 20231227 Rel. 84005. I tried the first suggestion but it didn't work, about the second option: if I only use 2.4 (instead of 2.4&5) wouldn't it slow down all devices...

I have 3 deco m4 installed, almost all devices connected properly to the network, but 1 TV and all sonos devices can not connect to it. Any idea why?