You can call a function in JavaScript with which you can change the z-index of the popup.
Something like this:

<button onclick="popup()" value="open popup">

Also make the popup. I am just making a rough one:

<div id="popup" style="z-index:1000; position: absolute;">Some code</div>

Remember to set the z-index at behind and the position. Then for JS i will make it simple in case you can’t code JS

function popup(){
document.getElementById("popup").style.zIndex=-1;//basically changing the popup's z-index
}

This will just change the z-index of the popup which you must create yourself

Edit: Stackoverflow modify automatically the Amazon links when you click, so for see the popup, select, copy and paste the URLs in the browser.

On Amazon there is a link to open directly a side popup, like this:

https://www.amazon.com/dp/B07FKTZC4M/#aod (#aod open the popup)

where We can enter some filters. I tried different ways with no success to generate a link that open directly the site popup with new filter pre-applied.

So i need a link that open this page with “new filter” pre-applied:

I tried different solutions, but don’t work, for example:

https://www.amazon.com/dp/B07FKTZC4M/ref=aod_f_new#aod

https://www.amazon.com/dp/B07FKTZC4M/ref=new#aod

https://www.amazon.com/dp/B07FKTZC4M/#aod_f_new=true

https://www.amazon.com/dp/B07FKTZC4M/ref=aod_f_new=true#aod

https://www.amazon.com/dp/B07FKTZC4M/ref=aod_f_new?ie=UTF8&f_new=true#aod

I see some informations on source page, maybe that help:

Question: Is there a way to create a link that open directly the side popup with new filter pre-applied? Maybe adding some parameters to the URL.