I am very familiar with the Kansas data (which is old), and many studies like it.
None of them (to my knowledge) try to measure mask WEARING as opposed to mask MANDATES.
Mask MANDATES are a political issue, and rightly so, but they don’t tell you how many people, of what age ranges, wore masks in indoor public areas during times of sustained transmission. Many people in non-mandate areas, especially the elderly, wore masks and many people in mandate areas, especially minorities in Southern California, never wore masks.
So all the papers flowing out of the Kansas counties dataset tell you nothing about the effect of masks on transmission.
Do you know how many randomized cluster trials CDC has done on this question since February 2020?
Zero.
Would there be more mask wearing in the mandate counties and cities than in the no mandate locations?
Hmm, while the study tried to create similar populations, did it recognize that maskers might behave differently from non-maskers? For instance, there may be differences in HCQ, Ivermectin and vitamin D.