I don’t know them specifically, when I want to use something quick I use FacetWP. When I have the time I build all the code required for the search myself, which is based on the first link I posted, the Dynamic $_GET parameters section of https://www.advancedcustomfields.com/resources/query-posts-custom-fields/. As far as I know there are no “free” plugins that will do searches based on ACF field types, or I should say, they will work on the “Basic” field types, but not on any of the more complicated ones.
