To turn off the 5G network, please go to Settings > About this machine > Version information > and click "Version number" for 7 consecutive times to return to the setting interface. Search in the settings page, enter "Developer Options", find the "Enable 5G" switch in the network and turn it off (you can control the card 1 or card 2 separately and turn off the developer options without turning on the 5G switch). If you have other questions about the 5G network, you can call the customer service of the corresponding operator for further consultation. Please forgive me for the inconvenience.