Insert row - copy formula from above using a protected sheet

[JuniorB]

Hello - Hope all is well. I'm looking for a solution where if I insert a row, the formula for the end column is copied from the cell above.

The sheet needs to be protected and the Select locked cells needs to be preferably unchecked as well. The Select locked cells can be checked if need be when protecting the sheet. Format rows and Insert rows are checked.

Thanks a lot for any solutions.