Consider a mesh system such as the Deco or extenders such as the RE650 which allows Access mode which allows the extender to be connected via Ethernet cable since your home is already wired.

@ScottDonahue 

 

I was thinking mesh like @ArcherC8.

 

When you add the need to have all networks the same and seemless roaming between the units is what a mesh network will provide.

 

I prefer the M9 with the dedicated wireless backhaul (5GHz), similar to being wired, but with a wirless band not accessible with wirless devices. With two nodes you can get about 4500 sq ft coverage, and can have up to 10 nodes. Drawback to having Decos is there are only two Ethernet ports on each node so you will need a switch if one of the satallite units needs to wire more then two devices. 

 

In any case you can go with the three AX6000 if that's your plan. You can make all the networks the same, but depending on what node the wirelss device connects to will be dependent on the device itselt or what threshold it has when deciding to connect to another network. Easiest way to manage all of them would be to use the Tether app.