Adding an additional WIFI router to my existing ORBI system

I have an ORBI system in my home with a router/modem in my basement and a wifi repeater upstairs.  The router/modem has the network in port and 3 LAN ports.  The repeater upstairs has 4 LAN ports to hook to for whatever I would want on the network.  My internet provider buried a nework cable between my house and my shop building that is appx. 100 ft away when they were doing fiber install in our town.  I decided I wanted to get it all finished up finally and at this point all we need to do is get another network cable from the modem in the basement back to the junction box on side of the house.  The installer suggested that I just buy another ORBI router that would get plugged into the network cable in the shop.  This way the WIFI network would all be the same as in the house and I wouldnt have to switch back in forth when I carry devices to and fro.  Just curious what router I would need to buy to do this?  Buying another repeater wouldn't do any good as it is designed to pickup and repeat the WIFI as well as provide LAN out ports, not to have the signal brought in to a network port and then broadcast the same WIFI.

Thanks