It helps if you use different font formatting in the header.
Different Font name and Style (bold and/or italic,) size, underline.
Number Type = General
Alignment , Horizontal and Vertical = Center
Borders (at least under) the entire header row.
Data Font Style should be "Regular."
Only format the data with data types (number, date, time, currency, text.) No borders, fills
You can use Conditional Formatting of the data, but not the header Row.
First select the entire sheet, (click the square above the Row Numbers, the to left of the Column Letters.
Remove all formatting . (Right click >> Format Cells) >>
Number = General
Alignment = General, Bottom and uncheck all Text Controls
Font = Regular, uncheck all Effects, Underline none, check Normal Font.
Borders = None
Fill = None
Now select each column, Format Cells >> Number and format as to its data type, (number, date, time, currency, text.)
Finally, select the entire header Row (1), Format Cells >> as noted above