Excel export doesn't format the column header like other columns when using option 50

https://live.datatables.net/ropoyema/1/edit

I'm trying to have all columns, including the header, left justified. Using option 50 does that for all but the header. How do I get the header to follow as well.

sheet.querySelectorAll('row c').forEach((el) => {
                            el.setAttribute('s', '50');

My test case for some reason I cannot figure out is not displaying the excel button. I did import the button js. The live app is on an intranet so I can't share a link there.