Orbi App Not Functional In AP Mode After Upgrade To AX4200

All, I replaced my Orbi RBK53 setup last night with the RBK753s (AX4200) units. I have the new Orbi in AP mode, exactly as the previous units were, with the exact same configuration settings so all of my devices reconnect easily. In the Orbi App (iOS), I was able to manage the RBK53 in AP mode without issue; however, after removing the old devices from the app and attempting to add the AX4200 units, the app never discovers the devices, despite being connected via WiFi to the new APs. I’ve read conflicting KBs that state that the app does not support Orbi in AP mode, or that functionality is limited. Clearly, the app worked fine with the old hardware, but is unable to connect to the new units. Has anyone encountered this problem and resolved it? My RBK53 and RBK753s are running the latest firmware as of 8/3/2020 (manually downloaded and applied), and the app is the latest version from the Apple App Store. Any help is greatly appreciated!