Combine entries query, but filter one section by field
{% set blogIds = craft.entries({
   section: 'blog',
   search: '-location:*',
   limit: null
}).ids() %}

{% set recipeIds = craft.entries({
   section: 'recipes',
   limit: null
}).ids() %}

{% set entries = craft.entries({
   id: blogIds|merge(recipeIds),
   limit: 12,
})



Limit null is only there incase you're paginating, can be removed else.

This is the easiest way I've found for effectively combining element queries.