@Nik_Scho For this feature to work, all Deco units in Deco mesh must support it. If feature disappeared after adding M4 V2 to Deco mesh, delete that unit from Deco mesh in Deco app and feature will...

@ezeb You can read more about WAN/LAN autosensing and topic discussion here: WAN/LAN auto-sensing I can only suggest workaround, it is up to you if you want to try it or not. Perhaps, TP-Link Support...

@ezeb For Main Deco to incorrectly auto-sense WAN/LAN port there usually must be device attached to LAN port capable of confusing Main Deco. Out of three you listed Raspberry Pi 4 is a suspect. To...

@Pedr057 Thick walls are WiFi signal killer. Does not matter what Deco model you try or what other brand of WiFi mesh. They all use same standard WiFi protocols to communicate. With WiFi, newer...

@Strat640 There is TP-Link AV600 powerline adapter on your network diagram. It should be compatible with Deco mesh, so try with it first. I have ZyXel AV600 powerline adapters, in my tests with them...

@LiorA Do you have your Decos from different geographical region than your phone? That may explain.