I agree with your first points, but the methods section states (somewhat unclearly) that they used this 4 point probe setup https://www.qdusa.com/products/ppms

I agree with your first points, but the methods section states (somewhat unclearly) that they used this 4 point probe setup https://www.qdusa.com/products/ppms.html https://www.qdusa.com/products/ppms.html I have more questions about that, like why not calculate sheet resistivity instead of just showing that the resistance hits the noise floor?