I bought two XE75 Pro to replace my 10-year-old AirPort network. For the last 10 years, I've had an Ethernet cable running from my old AirPort Extreme to a switch, which then runs into my AppleTV. In the old system, I never had speed issues.

however, the Ethernet connection from the new XE75 to the switch and then AppleTV is unusably slow. I have verified that the wifi connection in the house is very fast, but Ethernet coming from the Deco is terrible. It's very frustrating, and I have zero idea why this could possibly be the case. Shouldn't the Ethernet be just as fast if not faster than wifi in this case? I've rebooted the AppleTV several times, thinking perhaps old Ethernet info was cached, but that did t help.
 

to be clear, the two mesh routers are connected to each other via wifi--it is just the AppleTv which is connected to the primary Deco via Ethernet.
 

any advice or guidance is greatly appreciated.

thanks!