Replacing term/taxonomy archive pages with search queries

I’m not familiar with how FacetWP displays search results, but if it’s using the default (or a custom) search.php template, you could use a template filter to hijack the default hierarchy. See the Filter Hierarchy section of the Template Hierarchy page for examples. If you want more specific help update your question to show how you’d do this via wp_redirect() and we can help switching out the method.