Replacing Home Apple Extreme Router Network with RBK50 AC3000 Tri-Band WiFi

Followed your suggestion and set up the main Orbi as an AP plugged into Apple Extreme Router via a LAN port on both ends.  I turned OFF all other wi-fi on the Apple Router and also the Bell Canada DSL 5 megabit modem.

Setup satellite Orbi on a different floor and it connected fine to main Orbi via 5Gz special backhaul link.

On the Orbi app, the network map shows main and satellite on-line and a green dot.  There no top ring lights showing on the Orbi satellite unit itself,  but there's a constant mauve (or purple?) light illuminating the top ring on the main Orbi downstairs?  Perhaps the result of an AP setup as opposed to being plughged into the DSL modem?

The Orbi wi-fi network is operating fine and I'm able to use it from other devices and check its status both on the Orbi iPhone app and also from a Safari browser.

I decided to make the backhaul an Ethernet hard-wired LAN connection, so I plugged a LAN cable which leads back to the centralLInksys switch, into a spare connection on the back of the satellite Orbi.

I rebooted everything and now the satellite Orbi still has no light on the top ring, but on the iPhone Orbi network map it has a constant mauve (or purple?) dot instead of a green one, as it used to have when connected via the Orbi via 5Gz special backhaul link?  It also shows as off-line on in the app when clicking on it.  There's still a  constant mauve (or purple?) light illuminating the top ring on the main Orbi downstairs and that status never changed.

I disconnected the satellite Orbi from the LAN cable and went back to the Orbi via 5Gz special backhaul link and everything started working fine again.

I'm not sure what I'm doing wrong, but I followed the Netgear instructions for an Ethernet-based backhaul connected to a LAN switch.  Any ideas on how to get the AP working with this Ethernet configuration.

Thanks for your previous help.