How do I adjust popup height past page content and disable scrolling inside popup?

Has anyone been able to successfully extend popup height past page, so it scrolls naturally?

I’ve tried changing modifying height property, but the height is still limited to page height. There’s also checkbox called “Scroll (body)” which seems to do nothing, bc the body scrolls either way.

My goal is to create a separate experience when opening the popup, so the user can scroll like they would a normal page, and then exit by clicking the backdrop. It looks much more natural IMO for the actual page to scroll rather than only inside the popup.

If you go to Apple’s website for MacBook Pro, scroll down to Performance, and click “Go deeper on M4 chips” you’ll see a similar experience. The popup backdrop scrolls, not just the inner body. MacBook Pro - Apple