@jamesjamesa 

Can you also share "Map view" and "List view" screenshots from your app, to understand how your Deco connect to each other. Examples of these screenshots from my Deco mesh:

Please make sure all Deco units are visible on screenshots.

  @jamesjamesa 

  @Alexandre. 

  @jamesjamesa 

Thanks. Please also map your Decos from these screenshots to numbers on the first picture. Also, because you appear to have multiple Deco with the same name, how do you know which one is which?

  @jamesjamesa 

One more thing: your picture shows two Deco E4 and five Deco M5, your screeshots appears to show one Deco E4 and six Deco M5. Can you clarify that discrepancy?

  @Alexandre. Thanks. Few clarifications

1. Realized that 1 E4 is missing. I don't know who took it but it's not in it's place any more. 
2. Turned on the M5

3. There were names before but when the app updated it seems that it all returned back to M5 names. Now it's hard for me to know which is which. 
4. I'm ready to restart / start from scratch to make a good network. 

  @jamesjamesa 

If you want to start from scratch, these would be my recommendations:

1. Delete E4 from your Deco mesh and put it aside. With Deco mesh consisting of M5s only, that will unlock "preferred signal source selection" feature that you may need: How to select a preferred signal source on the Deco App

2. Give each M5 unique name, so that you know which one is which. You can match Deco to MAC address which is in the Deco info page and on the label on the bottom of Deco unit, or you can just delete all Satellite Deco from Deco mesh, leaving just Main Deco, and then add one by one and give them unique names. I would suggest deleting them and adding one by one, after you properly position one (more about that below) - only then add next one.

3. Each Satellite Deco must have good backhaul signal, two or three green bars. Start with Satellite Deco in rooms 1 and 3 - try positioning them in such a way that they have at least 2 green bars in Show List view, and that will correspond to Fair or Good signal in Satellite Deco info page. In these rooms, move them as close to the wall separating them from room 2 as possible. If you can't position them to have good backhaul signal, you are out of luck with rooms 1 and 3. The only other option is to try powerline adapters to link these Decos with.

4. When you are done with rooms 1 and 3, start adding Deco M5s while you are moving up your picture in the direction of room 4, 5 and 6. Every time you add new Satellite Deco to Deco mesh, it must have have good backhaul signal, two or three green bars. If it can't have that connecting to Main Deco, see if there is another Deco to which that Satellite Deco can connect with  good backhaul signal. To figure that, you may need to install WiFi analyzer on smartphone and map WiFi signal from Deco units at every place where you plan to place next Satellite Deco.

5. After rooms 1 and 3, next Satellite Deco should be the one in the place already on your picture, the closest to Main Deco (room 2) right behind the wall, in "Open Space." It is very important to find place for that Deco where it has at least 2 but ideally 3 bars, because later you may need to have other Satellite Deco connect through it. This one must have as good backhaul link to Main Deco as possible. If you could, move Main Deco as close to the wall separating it from "Open Space" as possible. Wall mount both on opposite sides of the wall separating them, if you have to, there are third party wall mounts available for M5s.

6. I would suggest not to have Satellite Deco inside room 4. The one that is right outside room 4, in "Open Space" - place it as close to room 4 wall as possible, and link it to Satellite Deco on the opposite side of "Open Space".

7. If that gives you reasonably good WiFi speed in room 4, do same for room 5: place Satellite Deco right outside room 5, in "Open Space", and also link it to Satellite Deco on the opposite side of "Open Space".

At the end, your "Show List" in Deco app must show all Deco having 2 or 3 green bars. There should be no Decos with 1 red/yellow bar. If you can achieve that, you have the optimal Deco mesh setup - I can't guarantee what WiFi speeds you'll see at different places of your bungalow, but what you get will be the best Deco mesh consisting of M5s can deliver.

  @Alexandre. Thank you very much. Will try to add a couple more M5. 
 

for now there is no need to switch to wifi6 devices such as X50? 

  @jamesjamesa 

WiFi 6 capable Deco such as X50 will not improve speeds in your situation. Thick walls are WiFi signal killer. Development of WiFi protocols goes in direction of faster speeds in exchange for shorter distances and more sensitivity to obstacles. Most likely if you replace all M5s with X50s you won't see any meaningful WiFi speeds improvement around your bungalow.

  @Alexandre. Thank you very much will try your advice. Appreciate it.