What I’d do in UiPath is pretty straightforward:

1. Read the new data from the first Excel file using Read Range (under the Modern Excel activities).

2. Read the existing data from the target sheet in the second file.

3. Combine them — put the new data above the existing data in a single DataTable using the Merge datatable activity or just by using newsatatable.clone and importing rows in the right order.

4. Write the merged table back to the target sheet using Write Range.

Basically, you’re replacing the sheet content with “new rows first, then old rows” instead of trying to physically insert rows at the top in Excel, which UiPath doesn’t handle directly.