WiFi whitelist?

I've seen messages from 2 years and older indicating no device white or blacklist exists for the xFi router. Bummer, never a great time to find extra $300+ I'll probably have to drop on a gigabit capable modem and router.

I did notice under admin console if you go to connection > wi-fi there is a WiFi control list.  It gives options allow-all(default), allow and deny.

Now if you add devices based on MAC address can choose if said services are allowed WiFi connectivity? Right? But if so, it does not work at all. Once it locked everything out, currently I split all three bands because was thinking that allow only setting wasn't working due to a device connecting under different frequency. Can anyone shed light? I have tested with both Android and iphone all device WiFi settings with privacy off. Kids have friends over, I want to control when and what kids can access on my network and often their devices are unmanaged. 

Finally, there is no option to setup a radius server right? Why do iphones flag connectivity with poor security on wpa3?

Can anyone recommend a device router or device I could use to meet my needs. I have the 1200mb plan. I'd love as all in one modem router with open or dd wrt. That or a highly recommended stock one. Thank you