Automate Weekly CSV to Sheets

Every week I receive a fresh CSV file and need its contents reflected in an existing Google Sheet. The workflow is straightforward:

• Append any brand-new records as new rows.
• For rows that already exist, surface the differences so I can manually review each one before the script commits the update.

I do NOT need any row deletions right now—only additions and updates.

A Google Apps Script, Python solution using the Google Sheets API, or another equally efficient approach is fine as long as it:

1. Lets me trigger the import whenever the weekly CSV arrives (menu item, button, or simple upload folder is okay).
2. Presents a clear, side-by-side view or colour-coded flagging of changes so I can confirm or skip each proposed update.
3. Writes the approved changes back to the same sheet without breaking existing formulas or formatting.

Please include brief setup instructions and a short README so I can maintain the script myself after delivery.