A:Answer Hi Steve,
Yes, the Eero Pro 6E has a 2.5Gbps WAN port and a 1Gbps LAN port. If your modem feeds the 2.5Gbps port, any wired connection from the Eero will be limited to 1Gbps.
You could use a 2.5Gbps switch between the modem and Eero, but it may affect some Eero features and control. For full functionality, it's best to connect the modem directly to the Eero's 2.5Gbps port.
Hope this helps!