Good question, thanks for sharing it with us! :)

So I am not sure if I understand correctly how you want to investigate this: If you are interested in KB article performance, then I would rather want to filter by the KB category they are in, instead of filtering by content type (article, discussion, etc.). But either way, I have some tips on how you can do this:

Moderation overview

If you switch to the old overview in Control, you will see that you can select a column “views”:

If you then filter by category and/or content type, you should be able to see which content got how many views.

Topic export

You can always get a topic export, which allows you to filter based on category and/or content type. It includes a column for views, but this count is (as far as I know) the total amount of views and not only for the selected time span.

Self-service dashboard (Beta, might not be enabled on your community yet)

While I see why you are checking the engagement dashboard (which hopefully will receive these filters soon as well, but I have no concrete date when this will happen), you can also use the self-service dashboard to get this information. Different than the engagement dashboard, the self-service dashboard offers these filters and will give you metrics on the unique users that viewed helpful content in the areas or content that you have selected. However, it does not produce a list of individual topics like e.g. a topic export would do.

I hope that this will help you further a bit, please let me know if you have more questions around this!