Can't acess Orbi RBK852 when configured as an AP

I'm trying to replace an R7000, which works fine in AP mode behind an erlite router which is in turn behind a Netgear CM1150v Comcast modem.  The R7000 still works OK, but I have to reboot it a couple of times a week.

I first tried to configure using the orbi iPhone app.  It came up in router mode without offering an AP choice, wifi was OK, but understandably no internet access.

So I connected laptop to a lan port, and configured through the admin portal, where I could locate an opportunity to use AP mode.  But I couldn't access the admin after switching to AP.  I tried DHCP with and without reservations, and I finally tried a fixed IP.  It was at that point that I noticed that wifi devices did have access to the internet, yet I still could not access admin.

I reviewed erlite DHCP reservations where I ran across three different MAC addresses, none of which matched the label on the bottom of the orbi.  I tried to access the three different IP addresses from LAN port, but none of them worked.  orbilogin.com/.net also did not work.

I called Netgear support and worked with them for about an hour, maybe more.  They brought up the possibility of my network, but I pointed out that after disconnecting the cable between erlite and orbi, I still could not access orbi.  Then they suggested that I return the unit I purchased 2 days ago, and replace it with a new one.  If it behaves the same, then they would escalate to engineering.

I'm new to Orbi, and I thought I would check in here.  I admit that I have not yet researched Orbi routing performance, but erlite is near gig speed and working well for me.  Should I consider moving the orbi router into a closet near the far end of my house, or should I continue to leverage the existing enet cable which is central to my downstairs.  I plan to use the satelite upstairs, where due to the split level of our house on a hill, it will server our backyard quite nicely.

Any advice on erlite vs RBK852 routing performance, and any advice on how to get AP mode to work, would be greatly appreciated!  Or should I just send the unit back?

Thanks in advance.