Currently, when several categories are selected, the system checks whether there is one or more app(s) that contain both categories. This can be useful to further narrow down a filter result due to a very crowded category.
However, if you don't know exactly which of the two categories the app applies to, you intuitively select both because you expect to get results for both categories.
I would suggest introducing a new mode and setting it as default (the current one can be moved to a new "filter options" dropdown if desired): This new mode shows first (alphabetically) the apps that match the most categories. Next, (alphabetically) the apps that correspond to the second most categories, and so on.
Currently, when several categories are selected, the system checks whether there is one or more app(s) that contain both categories. This can be useful to further narrow down a filter result due to a very crowded category. However, if you don't know exactly which of the two categories the app applies to, you intuitively select both because you expect to get results for both categories. I would suggest introducing a new mode and setting it as default (the current one can be moved to a new "filter options" dropdown if desired): This new mode shows first (alphabetically) the apps that match the most categories. Next, (alphabetically) the apps that correspond to the second most categories, and so on.