@mdonato For Main Deco M9 Plus Ethernet port connecting it to modem/router, if link speed on that port is less than gigabit you'll get "Abnormal WAN port speed" error message in Deco app: For LAN...

@Mamgrow Before you decide to replace M5s with something else, try things I list below. You can configure nightly reboot of Deco mesh in Deco app, it is under More/System. See if that fixes the...

@KMacD There is also such thing as "wireless print server," you can check it on Amazon. They advertise it as a tool to convert USB or LAN printer to WiFi. This might be less expensive than X20, but I...

@KMacD You don't need superior network speeds for printer, so you do have options. Powerline adapters make sense, but only if they can establish connection to each other. You would not know until you...

@vetgat Can't help you much with this, but at least problem description is much simpler now: "Main Deco 2.5Gbps WAN port can't negotiate gigabit speed with gigabit port of fiber modem."

@vetgat What if you swap connections on Main Deco: Fiber - to 2.5Gbps Main Deco port Switch - to gigabit Main Deco port