Hi there,
Definitely a great question in regards to creating a cookie popup. I’m happy to help!
You may find this helpful for creating the cookie popup: Show a popup based on a cookie — Free clonable template
The awesome @vincent provided a cloneable project specifically for popups with cookie consent.
You can view the live site at http://cookie-template.webflow.io/, and the cloneable project can be found at https://webflow.com/website/Webflow-Cookie-Template
Definitely, great question!