@Kossie Thanks, that tells me everything I need to know. As you may see from these screenshots, most of your Satellite Deco are properly positioned. I would only suggest moving 2sal Deco closer to...

@Kossie With what you have replacing just Main Deco M9 Plus with more powerful unit will not meaningfully improve speed and coverage for your Deco mesh. If you are interested in upgrade, there are...

@Kossie What is the speed of your Internet connection?

@gmlupatelli If your Main Deco connected to Router/Gateway (and not just to Modem), there is workaround.

@Pmailley Firmware in your Deco M5 is too old to be upgraded through the app. See this document for other options: How to Update the Firmware of Deco After you managed to upgrade firmware through...

@GCConsulting With Deco X90, the only way to do what you want is by connecting Office Deco to Living Room Deco with Ethernet cable. Using powerline adapters as a substitute to Ethernet cable...