Adding 2.4 ghz devices to Orbi

I know some people cannot help but patronize on these sites.  I am not a neophite with hardware/software setup.  I have tried to connect two brands of plug, one was TP Link and a La Crosse weather station.  The device instructions for all three devices basically say down load our app and follow the isntructions.  They have not required Bluetooth conection.  They reach a point where you select a network and input the password.  This step is supposed to give the device the network name and password.  It times out over and over and over.  

There are posts on the community which agree that if your phone is not connected at 2.4 ghz you cannot complete this step.  The only way I have been able to connect my devices is to turn off the Orbi and turn on an old router where the 2.4 and 5 ghz are seperate networks.  I connect my phone to 2.4 and the devices have configured on the first try.  This - and the device information through the Orbi attached devices screen accessed via the dashboard on the router which shows my phone connected at 5 ghz - is why I am making the conclusion that I am making.

More power to those have been able to connect using their phones connected at 5 ghz.  Were you using a Galaxy S9 running Oreo?  You say the Orbi handled the bridge between the two.  My experience says it doesn't.  Netgear needs to provide a simple way to accomplish this.  Until they do, I will keep my old router to connect new devices.