@Senna7004 

Have you considered to just add more M9 Plus Deco? 

Also, what is the speed of your Internet link? WiFi 7 hardware is usually expensive, and makes sense when Internet speed is over gigabit.

  @Alexandre. 
Thanks for the reply!

Did consider adding more M9 Plus', but they are almost similarly priced as e.g. the XE75's here, and then I would have WiFi 6 and larger range. So that's why I thought it would be wiser to go for a more modern option. Or is that foolish?

My internet speed now is 1Gbps, but might upgrade in the future.

Cheers 

  @Senna7004 

In general, newer WiFi protocols mean faster speeds, but shorter distances. WiFi6 will be faster than WiFi5 when standing near the WiFi node, but as you walk away WiFi6 will be more sensitive to signal interferences. 

The longest distance is WiFi 2.4 GHz (which came before WiFi 5), but it will be the slowest.

1 Gbps is more than M9 Plus can deliver, I have M9 Plus and tested their speeds. You'll need WiFi6 or better if you really, really need these fast speeds. 

If you don't mind telling, which region are you in? Here in Canada where I am, on Amazon Canada set of two Deco M9 Plus go for almost half the price of pair of XE75. 

  @Alexandre. Thanks for your answer! I did not know that these newer protocols had shorter distances. That would support putting the M9's in the outskirts of my house. 

Here (NE) the M9's are about 75% of the price of XE75's, so I thought if I spend a few hundred I might as well future proof my setup.

So then I think I will just put the XE75's in the center (and as main Deco), and M9's in the corners of my house. Or is the communication between the XE75's and the M9's significantly slower than if I would put all M9's?

Thanks again, really helpful.

  @Senna7004 

If you plan to add XE75, the best approach would be to have XE75 as Main Deco. 

How many additional Deco XE75 units you plan to add to your three Deco M9 Plus?

Do you plan to keep M9 Plus wired or move them where they will have wireless link to the rest of Deco mesh?

  @Alexandre. 

Thanks! I will add 3 XE75's, these will be situated on the ground floor (hall, main Deco), first floor and second floor. All are wired. Two M9's will be on the ground floor, one wired in a working room (thick walls), one wireless near the garden doors. The last M9 will be situated in the shed, wireles.

So two will move into the realm of wirelessness. That would work right?

  @Alexandre. 

Thanks! That is great advice, did not know you could do that. 

So then I will go for the 75XE's and do it all like this. Thanks again!!