@CHAACHO Can you return this 3-unit Deco X50 set? If you can, I suggest replacing it with tri-band 2-unit Deco X90 or Deco X95 set. As a tri-band it'll have separate band for backhaul. Deco X90/95 is...

@CHAACHO I see what you are trying to do. It is creative. I have a feeling that won't work, meaning you won't get double speed from third unit, but I can't find good explanation, why. You should try...

@CHAACHO You can't disable SSID broadcast on a single Deco unit, but there may be other methods available for you to convince devices that are near the third unit to connect to third unit. How far...

@Huge101 One more thing. Before you try upgrading M9 Plus firmware manually, power off Deco M5. So that your Deco mesh has only M9 Plus units online. Just in case.

@Huge101 That must be it. Firmware that old can't be updated through Deco app. Follow different, manual process: How to Update the Firmware of Deco

@Huge101 I double checked again, I have that option in my Deco M5. Just made screenshot and will put it at the bottom of my reply. I can only think of the following differences between your and my...