SOLUTION AT BOTTOM AFTER ORIGINAL DETAILS OF PROBLEM.
I have Google WiFi (not new Nest WiFi) in my residence. Google WiFi uses the same name for both the 2.4 and 5GHz band networks. Google WiFi leaves it to the device to choose which band it wants. See this Google support explanation.
The WYZE plug installation aborts as soon as it learns the presence of a 5GHz band. This is the same behavior I experienced with the CNCT brand “smart” inteliPLUG.
Since Google WiFi considers the same name for both bands a “feature” and not something that can be customized, Is there a work-around to make WYZE at least attempt to log in the network rather than abort the installation process?
SOLUTION: I changed the name of the Google WiFi network from JoMaRi-OnHub to JoMaRi-OnHub-24G. No other change in configuration was made. The WYZE Plug setup screen still warned that 5GHz networks were not supported but now when I provided the JoMaRi-OnHub-24G name and password, the WYZE Plug was able to connect and now operates without problem.
Of course, the downside of this solution is that I was forced to change the network settings on EVERY WiFi connected appliance and computer in the house.
I should also note that even though the WYZE cameras require 2.4GHz network, they were fine on my Google WiFi before the name change.
As far as I know I have not lost any functionality by changing the name, although I don’t know if I have any devices that REQUIRE 5GHz and might be misled by the new name.