Format Power BI report in SharePoint page

The built-in Power BI web part doesn’t expose an arbitrary height setting. Your report is roughly 7:1, so placing it inside a 16:9 or 4:3 container will naturally leave a large unused area.

First try the web part’s Display setting with Fit to width, and hide the navigation and filter panes if you don’t need them. That can reduce space inside the report, but it won’t change the web part’s outer aspect ratio.

The practical fix is to redesign that report page closer to 16:9 or 4:3, or split the wide banner into smaller report pages or visuals that fit the SharePoint section. Power BI Desktop supports a custom report-page width and height, but the SharePoint web part still controls its container.

If the exact 2500×350 shape is mandatory, you would need a custom SPFx/Power BI Embedded solution where the host controls the height. Avoid Publish to web for internal data because it makes the report publicly accessible. There isn’t a simple supported resize handle for this web part today.