PC: You can check whether the network band is 2.4G or 5G by viewing the properties in the Wi-Fi connection details.
Mobile: Some phone models allow you to view the corresponding band by tapping the Wi-Fi details page. If this isn't possible, try using a third-party app to determine it.
P.S.: Every router supports the 2.4G band. You can check the assigned Wi-Fi band in the router's management page
Link to the reference article on the equipment network configuration tutorial:Network Settings