In the Advanced Settings section, navigate to Wireless.
On the General tab, verify if Enable Smart Connect is turned on. If Smart Connect is enabled, disable it to distinguish the SSIDs for the 2.4GHz and 5GHz bands.
From the Band drop-down list, choose 2.4GHz. Set Network Name (SSID) to <xxx>-2.4G, where xxx represents the Wi-Fi name. Save the setting.
Also from the Band drop-down list, select 5GHz. Now, set Network Name (SSID) to <xxx>-5G. Save the setting.
After completing these steps, the new Wi-Fi names will be visible on your mobile phone's Wi-Fi settings page.
Note: After changing Wi-Fi names, reconnect the devices using this wireless router. The password remains the same unless changed.