Hi @mussa.butt,
I’m afraid there isn’t currently a way to set percentage widths for Data Grid columns.
You may be able to achieve what you want using a Repeating Panel containing Column Panels. Each column in a Column Panel is a fixed proportion of the width.
https://percentage-width-columns.anvil.app/
https://anvil.works/build#clone:DDBPAE4UIAWFP7MI=2NS47YZ4ZTHOUIGNWXQF6ZN5