Disagree. Use different SSID (network name) for the different frequency bands. Often when setting up IoT devices (especially using iPhone) you need to know that your phone is connected the 2.4 GHz network.If you have a mesh network, tethered or not, then they should be the same - but you often temporarily have to shut off 5 GHz during the setup phase of new IoT devices (easy, but often hidden deep into settings, can you hear me Eero…?).

Lots of incorrect information there. 2.4ghz is often used in combination with 5ghz because 5ghz does not have near the range of 2.4. As strength lowers, so does speed, and 5ghz actually becomes slower than 2.4ghz.

All routers still broadcast 2.4/5ghz by default. No manufacturer turns this off. They often use band steering and some have issues with devices negotiating which band to use, which is the reason so many recommend splitting off a 2nd SSID with just 2.4ghz