Thanks for the input! I finally found the link https://www.burningoc.de/blog/ncase-m1-and-the-rtx-3080-evga-ftw3The Impact indeed extends further down compared to the Strix, but I can’t see this having any measurable thermal impact. I’m using the Impact actually and don’t find this to be a problem.
However, I went ahead and decided to use an impact as well for the USB-C. My GPU temps on a 3070 doesn't go above 74 during timespy or port royal so I think I made the right decision to just go for the impact