Yes you can do that, and yes it requires some custom JS, but just a few lines.
I think you could do it with three parts;
Your interactions-based modal, which covers the page however you want it to, and contains a large IFRAME. That popup will also have a close button or wrapper area that is clicked to close the modal.
This is your item card, indicating the CMS / blog item you’re going to display. It has the preview, and the you give it a class that your popup is triggered from.
With this setup, each of your collection list items can be clicked, and will trigger the interaction pop-up with a big empty IFRAME. Make sure that’s all working the way you want it to.
In addition to Webflow’s interaction scripts, we need to add two other scripts to manage the content and the URL changes. They are attached to the same modal open / close trigger elements that have already defined.
Open script- triggers on a click on any of your collection item cards. It sets the IFRAME url, and changes the URL history to reflect the page you’re seeing in the IFRAME.
Close script - changes the URL back to the current page.