@Acorn50 

You may wish to also check outdoor access points and/or WiFi boosters. Not necessarily from TP-Link. 

For regular household TP-Link Deco units, their Operating Temperature: 0℃~40℃ (32℉ ~104℉). Your outbuildings, green, purple and yellow, do they meet that requirement? If yes, I may be able to recommend Deco model that meets your needs and placement of Deco units. 

  @Alexandre. 

Hello and thank you for your reply. The green and yellow buildings are my kennels and cattery so yes, they have heating and should fulfill the temperature limits. The purple building is a timber barn without heating and is on the diagram in case I need to place an intermediate unit between the house and the yellow building (if the WiFi signal won't reach directly to the yellow cattery building).

Thanks in advance

  @Acorn50 

I can give you recommendations for household Deco hardware. Outdoor WiFi range extenders, boosters and access points is not my area of expertise.

I'll start with the summary of what I can recommend, and will make it applicable to any WiFi mesh brand if you decided to try something other than TP-Link Deco.

In my opinion, this is what you will need:

1. WiFi mesh that is WiFi 2.4GHz and WiFi5 capable.

The mainstream WiFi mesh nowadays is WiFi6, WiFi6E and freshly minted WiFi7. These never WiFi versions deliver faster speeds but for shorter distances and with less tolerance for obstacles such as wall. They might not give you a benefit for longer distances comparing to WiFi5.

2. Ability to manually configure daisy chain.

Not every Deco model and not every brand of WiFi mesh allows you to configure how WiFi units must connect to each other. For you, this is an important requirement.

3. WiFi mesh that is tri-band.

It is more of recommended than "must have," but regular dual-band WiFi mesh cuts WiFi speeds by half on each hop. Tri-band mesh uses extra band for communication with WiFi units, that feature cuts WiFi speeds by about 30% on each hop. When you have more than one hop, that'll make the difference.

Based on all of this, my recommendation for you would be Deco M9 Plus. It fits all the above requirements and also has an extra benefit: due to its form factor, it can be wall or ceiling mounted, using third-party wall mount holders. If you are interested in that option, let me know and I'll discuss what wall mount holders you should get.

If you would rather have WiFi6 Deco model, as your Archer is WiFi6 : Deco X55. It is not tri-band, but WiFi6 should be faster than WiFi 5.

In total, you will need 5 Deco WiFi units, that includes Main Deco you will place in the middle of farmhouse, where your Archer C7 is.  

Other recommendation: make sure you buy Deco hardware from the place with minimum 2-weeks and straighforward return policy. Until you try, you would not know if Deco mesh will work for you.

An additional challenge is security cameras: not all of them are WiFi mesh friendly. If you find you can't connect security cameras to Deco WiFi mesh no matter what you try, you will have to return Deco mesh hardware (or replace cameras with newer models?).

  @Alexandre. 

Thank you so much for your advice.

I will certainly look more into it and start researching about compatible security cameras as that is the main reason for wanting the upgrade.

Thanks again