A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Use Power Query.
You can import files from folder or multiple single files and append them in PQ.
Furthermore you can create additional columns and calculate the values you need.
Load the result into a worksheet (if really needed).
In the sheet you'll get a table, in there you can also add additional columns and use formulas.
If you refresh the query, the new CSV data is loaded and your additional columns are preserved (also sorting, etc.).
Andreas.