Thank you for your explanation.
But there is no way to do that. Because that is woo compare plugin feature, so we can't make that.
If you click the compare footer link, it will must be redirected to the compare page.
We can't show the iframe popup content without redirect.
But you can open the compare page on new tab. So when you click the compare link. compare page will be opened on the new browser tab.
If you have the other questions, please let us know again.
Best Regards, C-Themes