Thank you for contacting Syncfusion support.
We have checked your query. When you double click on column header, it will behave like Auto column sizer. So, column width will be calculated based on header and cell contents. When you enable the Filtering and Sorting for column, the width of column remains the same. For header cell, width will be calculated by considering header text, SortIcon and FilterIcon. The default width for filter icon is 20, sort icon is 18. If you want to exclude the FilterIconWidth and SortIconWidth of column header, you can set the value as Zero.
To change the FilterIconWidth and SortIconWidth of column header, you can use below link.
For more details about ColumnSizer, you can refer below link.
Please let us know if you have any query.