Serial numbers have been added to end of some files because the names are the same.
Serial numbers have been added to the names of some files because there are files with the same names in the new save destination.
To delete the serial numbers added to file names, refer to You Want to Delete the Serial Numbers Added to the Names of the Files (Android 11 or Later).
The files that have serial numbers added to their names can be checked by tapping [Results of the file migration] in the message.
If some files have serial numbers added to their names, the files can also be checked from [Results of the file migration] under [File Management] in the [Preferences] screen.