Please try the following:
1. Turn on the USB debugging function, go to Settings> About Phone> Software Info, click Build Number continuously. After 'You are now in developer mode' appears, go to Settings> System> Developer Options> USB Debugging, and enable USB debugging.
2. If your phone charges normally and the USB port is working, plug and unplug the data cable and select 'File Transfer'.
3. If you can't select 'File Transfer', restart your phone and computer, and try to connect again.
4. Replace the data cable, ensuring the USB ports of your phone and the computer are normal.
5. If the computer has a phone driver software installed, and a new device prompt appears when your phone connects to the computer, it's usually a driver problem. In this case, reinstall the driver.
6. Back up any important data and restore your phone to factory settings.
If the issue persists, contact the Nothing Support Team for further assistance.