How to: Blur effect on background frame when overlay is popping up

I have a frame. I have another frame (overlay).

My intention: Blur the background Frame when the overlay is opening.

Background blur on the overlay didn’t worked. Presentation mode: nothing. Why and how can I fix this?

How I want it to look (made in Adobe Illustrator):

You are not alone. This has been a battle for years trying to get Figma to add this.

The only way i know to do it in Figma is to make a background blur a part of overlay