I had already made an entry in the Foum about it.
https://www.telerik.com/forums/is-there-a-way-for-percentage-column-widths
Link to the demo with the css workaround:
https://stackblitz.com/edit/angular-y8y55s
The main intention is that I want to be able to specify the column width in percentage values rather than fixed pixel values.
There are some edge cases that must be considered: