Thank you, Tin, for your prompt answer. I should probably clarify that the reason why we want to back up the SharePoint list by duplicating the list, is because the rows contain attachments that will be lost if data is exported to spreadsheets or similar software.
We use Microsoft Access as a front end, but, at certain point, the programme began to return errors when converting the linked table into a local table -due to multiple well-known but apparently not-yet-addressed-by-Microsoft problems (i.e. System Resource Exceeded, could not find object,...)-. The SharePoint list is definitely bigger than 50MB (but smaller than 2GB).
If duplicate a SharePoint list bigger than 50MB is not possible, are there any suggestions about how to back up the data (incl. attachments) into a file that can be imported into SharePoint, Access or any other RDBMS?