@NikSf153 

You will not need to add a Deco.

This is how you new network layout will look, with Deco mesh running in Access Point mode:

If you have enough Ethernet ports on new router you are going to get, you can even remove switch from the layout by wiring Deco directly to the router:

In both cases, to avoid issues, I would suggest to get TP-Link brand router, which should support Deco Ethernet backhaul. Check the following model: TP-Link N300 WiFi Router (TL-WR841N).

In my region (Canada) they sell it on Amazon.

  @Alexandre. Oh great. This is immensely helpful. I will have to use the switch because it is powering the decos via poe. Will try out a tp link router and update this thread with the results. Thanks again for your prompt replies. Warmest Regards

  @Alexandre. Did the setup...both deco x50s in ap mode connected via Cat6 cable to tp link poe switch sg1210p which is connected to a syrotech gigabit router/modem supported by my ftth provider. Now on my deco app I can see status as in the attached image. Please note that there used to be a wifi icon above the line between Living Room and Family Room deco. That is gone. The network is working fine all around in the house. Is the ethernet backhaul active? 

  @NikSf153 I think I got it now!! Manual Firmware upgrade 1 deco at a time. Decos are in AP mode. Smart DHCP is enabled. "Turn Off Lan DHCP" is disabled on Syrotech main router/modem and I have switched off that one's radio. Thank You for your guidance. Feels like a puzzle sorted yayyyy ❤️

  @NikSf153 If you tap the image showing the two Deco, it will show more details about each Deco, including the backhaul used.  You can obtain more details by taping on each individual Deco (in the table view).