Restrict KB articles based on user roles

Hi, the plugin is great and does pretty much exactly what I want.

The one exception is that I need to restrict articles based on user roles, or lack thereof, i.e. if you are not logged in, you can’t access the knowledgebase at all, and if you are logged in, the articles you have access to are limited by what your (custom) user role is.

I’m trying to use custom code in my theme’s functions.php to do this, based on an answer I’ve found here: https://wordpress.stackexchange.com/a/113515/118037

There is of course the possibility that code just doesn’t work, but I’m wondering if it is because the knowledgebase is using custom taxonomy?

Basically any hints you can give would be helpful, I’m pretty confused as to where to go from here. I’m a PHP dev but very new to WordPress.