Which ORBI? AT&T Arris BGW210-700, need wpa3 and bridge, 4000 sq. ft.

it contradicts to any normal network design. You talk to an network engineer here dealing with the fastest real IP networks in the area and used to deal with 100GbE/40GbE/25GbE/10GbE the subject Orbi systems can handle 10 GbE, 5 GbE, 2.5 GbE wired backhaul and performing wireless backhaul connections on 5 GHz 1GbE/25GbE/10GbE/on SMB and home networks, doing  and just released from the hospital following a brain surgery having to read about bridged WiFi - seriously, this is something ATT offers to the poor customers over there? Sorry, i can't develop much (read: any) motivation for such a **** design. This is like to put the cart before the horse. this is why there was no future for Apple networking. 8-)