Inquisitor wrote

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Hardware Version :

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ISP :

I have my house covered by gigabit ethernet and I want whole house WIFI as well.

I want to connect all 3 Deco AC1300 to wifi, not just one

I have two questions:

1. Is the optimal layout?

2. Will this free up the back-channel?

That should work fine as a Ethernet backhaul. Using Ethernet backhaul will give better performance, but you will always have the 2.4Ghz and 5Ghz available. While the Deco units are wirless they are half-duplex, while wired, they opreate a full-duplex.