Cannot connect to WiFi when Maximize Compatibility is on

I set up the WiFI network on one of my Firewalla Purple and use it internally to connect (a few) MacBooks and iPhones. But I needed to add some IoT devices to the network and activated the "Maximize Compatibility" to enable 2.4GHz. As soon as I did, the IoT devices worked but the MacBooks could no longer connect to the network. Running a WiFi tester, I see the 5GHz network no longer exists.

Is there a way to get both 2.4GHz and 5Ghz at the same time? Thanks

BTW: I tried the beta and it did not work either.