This is not correct. Many such devices are configured via mobile apps that instruct the device on which WiFi network to join. This is done during setup when the mobile device creates a connection directly with the device being configured, via either bluetooth or an ad hoc WiFi network. The router band used is a matter of user choice, whether the choice is implicit due to it being the network the phone is already connected to, or explicitly chosen from the networks available to the user.
An example of this is the Amazon Echo. At configuration time the Echo device creates an ad hoc WiFi network and the user must then temporarily disconnect his/her mobile.device.from the home network and to the Echo’s ad hoc network. Then they must use the Alexa mobile app to select the preferred home WiFi network. The ID and password (if one is established) of the chosen network is then communicated to the Echo, which will then tear down it’s ad hoc network and connect the the one selected by the user.
The differences between that and the Anova are that the Echo supports both 2.4 GHz and 5 GHz, the Anova app uses a Bluetooth connection to configure the APC and the WiFi network used is the one to which the mobile device (phone or tablet) is currently connected…which is why the instructions tell you to be certain that your phone is currently connected to a 2.4 GHz network. But in both cases the network used is still ultimately one selected by the user.
Such devices cannot choose a network on their own and “simply work”, for several reasons that should be obvious.