Querying posts globally based on custom taxonomy with its own taxonomymeta table

For those running into issues in the future, this is what I did:

I made my pre_get_posts function that queries the taxonomy as normal for testing if an taxonomy ID is not in a list:

            $q->set( 'tax_query', array(array(
                    'taxonomy' => 'tax',
                    'field' => 'id',
                    'terms' => tax_get_inactive(),
                    'operator' => 'NOT IN'
            )));

Then, I implemented my tax_get_inactive function as seen above, to query my taxonomymeta table and build an exclusion list. Not the most elegant way, but it works and the exclusion list can easily be cached if performance is in mind.