I've got a shop on the back of my property and want to improve the wireless backhaul link reliability.  The top "BEFORE" works just fine but the signal can be unstable/weak as this is a metal building.  I simply want to swap the first RT-AC68 bridge INSIDE the shop with the CPE210 OUTSIDE the shop to create the wireless backhaul.  BRIDGE mode in ASUS speak is basically wireless client.

I've tried to show my "before" and "after" in this drawing.

I have the CPE210 in "CLIENT" mode, no dhcp server. automatic IP with a reservation set on the main router and fallback IP as the same IP (192.168.200.5).

If I plug my laptop directly into the LAN port of the POE injector I get an IP from the RT-AX88 in the house as expected.  The link is strong and the bandwidth MORE than acceptable for my needs.

HOWEVER, when I plug in the RT-AC68U (WAN PORT) it DOES NOT get an IP but WINDOWS/ANDROID devices I connect either wired or wireless, DO get IPs and internet access.

It appears NON WINDOWS/ANDROID devices ike IOT/iPhones will NOT get IPs when the CPE210 is used instead of the original RT-AC68U media bridge.  I also have tried other brand equipment and modes with the same results 

I know it's a lot to take in but I'm baffled.  I've spent a LOT of time on this!

ANY HELP APPRECIATED, TIA!