@XFSPortfolio 

Deco is WiFi mesh system. If you have Vodafone THG3000 WiFi router in the centre of your house, which is quite good location, why have you decided you need WiFi mesh? Is it because you don't have good WiFi coverage in some places of your house, or is it because of some features TP-Link advertises for its Deco? If features, what are they?

Also, among different Deco models, why have you decided on X20? Nothing wrong with it, but it is a budget model from Deco X20/X60/X90 lineup supporting WiFi6. TP-Link also offers Deco M4/M5/M9Plus lineup for those who are OK with just WiFi5.

Do you plan to connect Satellite X20s to your home network by Ethernet cables, or do you plan to have them wirelessly connected to Main Deco?

Finally, what is the speed of your Internet connection, and do you plan to upgrade it to faster speed in the next 3-5 years? If you do, what that upgraded Internet speed would be?

@Alexandre. 

I do have some wifi problems especially in the kitchen where it shows poor signal on my devices, if using my laptop over wifi in a bedroom it buffers too. I have a Samsung S21 Ultra which supports Wifi6 so thought that was a good idea also a bit of futureproofing too around the house as more things will get added as always. My mate has same THG3000 but with a few years old BT disc system as has Ring doorbell, CCTV, solar inverter running wifi monitoring 24/7 in the attic and thought I could do similar but with newer equipment.

The plan is to use no Ethernet cables to the Deco units on the ground and upper floor. I also have some devices running in the attic so it would also benefit those with the upper floor unit.

I currently have Vodafone FTTP which I've had for over 18 months and currently get approx 550 up and down with the option of 1GB if I want to pay the extra but don't see that I need that or justify the extra cost.

Hope that's enough info - thanks

@XFSPortfolio 

You really did your research.

For your Internet speed you'll need WiFi6 mesh. With Deco nodes connected by Ethernet, you don't need anything more expensive than X20. You made a good selection of hardware.

Deco initial setup and configuration is easy, as long as you follow exactly steps outlined in the document that comes with Deco pack. 

Hints and suggestions.

1. You should run your Deco mesh in Access Point mode. By default, it is in Router mode. After you configured first X20, which will become your Main Node according to TP-Link terminology, change Deco Operating Mode to Access Point. Then, continue with adding remaining X20 to your mesh. I'll add Deco app screenshot at the bottom of that post, where this setting is.

2. If you will set your Deco WiFi with same SSID and password as on THG3000, after you turn off WiFi on THG3000 all or most of your WiFi devices should seamlessly reconnect to Deco mesh. I would suggest changing THG3000 SSID to something different after you have your Decos running, just to make sure devices won't connect to it if its WiFi is accidentally enabled later.

3. With Deco running in Access Point mode, you can still use all Ethernet ports of your THG3000. One will be for Main Deco, but X20 has two Ethernet ports, you can connect anything wired to that second port.

Which means, you might not need to buy an extra switch, especially if you thought you can't use THG3000 Ethernet ports.

Enjoy your Deco mesh.