So you would lose the internet connection despite having a good signal strength for instance? I would suggest splitting your SSID into two separate SSIDs, one for the 2.4 ghz broadband and one for the 5 ghz. Once you do, you'll be able to select either one manually and it should fix the issue you're facing.
To do so, you simply have to connect to your Hub by opening your favorite browser (I.E. Internet explorer, Edge, Chrome, etc.) and then typing "192.168.0.1" into the URL bar. If this is the first time you log into it, you'll have a prompt for the language and then for the password. You can find the "settings password" on the sticker located underneath the hub.
Once you're in, you simply have to go under "Advanced settings" --> "Wireless" --> "Security". At this point, you need to check both "WiFi Network Name (SSID) broadcast" boxes under 2.4 GHz WiFi configuration and the 5.0 GHz WiFi configuration to "Yes". You'll also need to assign a different name for both networks, since they'll be split afterwards. I suggest you keep the same name and just add "-2G" at the end of the name for the 2.4 GHz one, and "-5G" for the other one.