Hey Danny!
I suspect that your Join is not joining any data successfully.
In that recipe, it is using an older version of the Find/Replace step, which can be confusing. In yours, you will want the Find and Replace step you have to essentially remove the first part of the URL. So in the recipe, the URLs are start with /essential-guide-to-airtable/ and then after that is the important slug which matches Webflow.
In your flow, make sure your Find and Replace step is finding /whatever-your-urls-start-with/ with slashes on both sides, and replacing it with nothing. Just leave the replace field blank.
You will know this is working if you look in the Join step you have, and look at the far right two columns from GA, and see that they are not blank.