Check this out, its a issue recognized by vw and they insert lubricant to work around it.

Hey guys The creaking is from the placeholder foam under the glass roof. It is a recognized issue from vw and they will try to fix it vis inserting silicone lubricant. There is a TPI technical product information of vw about it. My Id hst the same issue and it got 80% resolved. It is in German but y...