Hello, I have an internet connection of download 200 mbps and upload 30 mbps.

I have 7 Deco M5 at home (its a big house). I've attached the network topology below:

Deco 1 is connected directly to my modem via ethernet (Wifi router mode).

Deco 1 is then connected to switch via ethernet

Deco 2 is hardwired via ethernet to the switch connected to Deco 1

Deco 3 is hardwired via ethernet to the switch connected to Deco 1

Deco 4 is wirelessly connected to Deco 2

Deco 5 is hardwired via ethernet to Deco 3

Deco 6 is wirelessly connected to Deco 3

Deco 7 is wirelessly connected to Deco 3

They all broadcast 3 SSIDS:

SSID: A for my personal devices (2.4 / 5 ghz)

SSID: B for guests (2.4 ghz)
SSID: C for iOT devices (2.4 ghz)

I've observed that when i connect to 5ghz i get the full 200 mbps download / 30 mbps up speed but when i connect to an SSID which broadcasts only 2.4 ghz, I get only 2 mbps download. If i enable 5ghz on the SSIDs B & C, and if my device is connecting to the 5ghz spectrum, I'm getting the full 200 mbps down / 30 mpbs up but as soon as I shift to 2.4 ghz its back to 1.4 - 2 or max 8 mbps.

I've tried testing this from each individual decos with the same results. I did the channel optimization, and it says that everything is perfect. I tested this scenario from several devices (smartphones and laptop), 1 foot away from the DECO with the same results.

Please help!!