Excluding a class or element from a backdrop filter

Hello lovely people.

I’m struggling with an animation i’d like to implement. You can see the desired effect here: Video

I’m using a div on which i applied a backdrop filter. However, i need the background (body) to be excluded from its effects.

Already searched the internet and asked our friend AGI v4 but i’m not able to find a solution to this. Maybe there is a different approach to achieve the desired effect?

Thank you for your suggestions!

Here is my public share link: LINK
(how to access public share link)