Hi @the_miked
The most effective solution is to use tags as they are supposed to be used.
Instead of all this meta_query and merge logcic, which will drasticaly slow down your website, why not just use the taxonomy to filter the posts as it was created to do?
When you edit the field group, you will see a setting on your taxonomy field that allows ‘load and save taxonomy term connection’. This will create the link between the taxonomy term object, and the post so you can perform normal a WP friendly tax_query.
Thanks
E
