Model - MR60
Firmware - 1.1.6.124
There are some other threads about a MR60 mesh issue where IoT devices that don't understand 5Ghz wireless need a method to disable 5GHz and exclusively enable 2.4GHz instead to allow those legacy IoT devices to connect. The only thread I see marked as "solved" points to an odd workaround where you disconnect the satellites, and wrap the main router in tin foil.
Some time in 2022, a better solution was created by Netgear: https://kb.netgear.com/000063027/Can-I-create-separate-2-4GHz-and-5GHz-SSIDs-on-my-Nighthawk-Mesh-Wi...
What's not made clear there is that you need to be running firmware version 1.1.6.124. While on the factory-installed v1.1.6.122, the menu choice described in the above procedure doesn't appear. In addition, the automatic firmware detect didn't move me to v1.1.6.124, but I manually found the new firmware here: https://kb.netgear.com/000064880/MR60-MS60-Firmware-Version-1-1-6-124
After installing that update, the Advanced Setup > Customize WiFi Network menu choice showed up, and I was able to create a 2.4GHz SSID that allowed my legacy IoT switch to connect. Hope this helps.
