Installed new mesh WiFi system, Roon zones vanished

Is that an Eero 6 or Eero 5 Pro? I believe multiple users here have Eero 5 Pro working in Roon.

This post documents problems with Eero 6:

Assuming you still have the Apple router, restore it for routing and DHCP services, but disable the WiFi. Turn the Eero into bridge mode.