Update Header on Google Spreadsheet

I need to update header on my Google spreadsheet. I cannot use Write Range, Append Range and possibly for each on columns as the spreadsheet has a lot of data. The purpose of my updating header is, as I am adding dynamic column to the datatable, I need to update the header for newly added columns.

Write Range under GSuite does not allow me to specify the range, it just allows me to specify starting cell.

@Palaniyappan, looking forward to your thoughts.