Hello @Nicola_Imperati
you mean this extension:
you can convert the entire TinyDB to a text file.
You can also convert the TinyDB into a text file using blocks without extensions:
I don't understand what you want to do. If you have a TinyDB and you want to create a backup in the same app, copy the entire TinyDB and another TinyDB_backup.
If you want to have a backup outside the app, you can save it to CloudDB, FireBase, GoogleDrive.
You say it has a single tag with 457 values, how size are all values?