Netgear EX6110 wifi range extender now requires manual allocation of IP addresses in Linux

I have a Netgear EX6110 WiFi Range Extender that was purchased in February 2023 and is still under hardware warranty. Previously it could be setup without much effort with my Optical Network Unit (ONU) and D-Link DIR-615 router on my Manjaro Linux desktop.

Upon my ISP's recommendation, I replaced both the ONU and router with a single Net Link GPON ONT  unit, combining both the optical network unit and the router in one case. The EX6110 did not work out of the box with the new setup, and I was on a considerable support discussion with the Netgear support staff to no avail.

I have finally managed to get it working by setting a fixed IP address for the EX6110 on my router and on the EX6110 itself. However, the device is unable to assign IP addresses automatically and I need to manually select the IP address and DNS server before the EX6110 functions as an extender (see screenshot).

One curious fact is that the EX6110 shows up with MAC address 02:0f:b5:f2:ba:0a on my Net Link router whereas the sticker on the bottom of the extender has the MAC address 80:cc:9c:f2:ba:0a. Are there any reasons for this?

My three questions are:

1. What should I do to get completely automatic setup on my KDE connections panel as I enjoyed previously?
2. Does the EX6110 have a builtin DHCP server that may be accessed and activated to avoid manual allocation of IP addresses as shown in the attached panel screenshot?
3. What settings on my (main) router should I look at to troubleshoot and solve this sort of behavior to get IP addresses automatically?

Please see the attached screenshot to better understand my situation.

Thank you.