I had the same problem with a smartlite. My prob was I just didnt get it flashing for setup quickly. It was flashing but about on off every two or 3 seconds. The correct flashing is like on off every second. Once I did that it worked without changing any set up - it found 2.4 on its own
@K1200s -- simple solution: login to the Shaw cable-modem, choose "WiFi setup", and temporarily disable the "5G" network. Then, connect all your devices, including your iPhone, to the remaining "2.4" network. Finally, enable the "5G" network -- devices currently connected to that "2.4" network will stay connected to that network. You may want to force your iPhone to connect to the "5G" network, for faster performance.