Hello, @owntone !
Brandon here with the Webflow Customer Support Team!
I will be happy to help you with your issue regarding Disqus integration.
What I see so far is that you have your code right, except for the page-identifier.
This is where the Page ID will need to be added. Each Page has its own unique ID for making changes and updates.
You can find a Zapier video made by @rileyrichter a few months back and it will show you how to get that Page ID. You will need to make a new field in your CMS and then use that Field instead of the Slug Field you currently have connected to it.
Here is that video link: https://www.youtube.com/watch?v=nb-63W0ey08&feature=youtu.be&t=1161
Good luck and enjoy!
Please let me know if you have any other questions,
~ Happy Designing ~