Is is possible to plug in all Deco units to the main router's LAN ports and get wired ethernet backhaul? I tried this last night and the app couldn't find the 2nd unit.  I set it up like this:

1. Setup 1st Deco in app (Checked box for I have a modem/router)

2. Setup 2nd deco upstairs wirelessly first

3. Unplugged 2nd deco and connected ethernet to wall (Main/ISP router's LAN)

4. Switched to AP mode and doesn't work.

And in AP mode, does the mesh tech still work? I want to avoid having multiple SSIDs based on what floor we're on.

I have ensured they are updated.