Hello Trevor,
I managed to find why the request to the db takes so long and also which are the query that are responsible, so below are the files and also the queries :
1) – wp-content/plugins/search-filter-pro/public/includes/class-search-filter-cache.php:1344 time is 4.4 seconds
Query is : SELECT post_id, post_parent_id, field_value_min, field_value_max

FROM (SELECT min_table.post_id as post_id, min_table.post_parent_id as post_parent_id, min_table.field_value as field_value_min, max_table.field_value as field_value_max

FROM (SELECT post_id, post_parent_id, field_value

FROM wp_search_filter_cache

WHERE field_name = ‘_sfm_mf_2’) AS min_table

LEFT JOIN (SELECT post_id, field_value

FROM wp_search_filter_cache

WHERE field_name = ‘_sfm_mf_2’) AS max_table

ON min_table.post_id = max_table.post_id) as range_table

WHERE cast(field_value_min AS DECIMAL(12,2)) >= cast(‘0’ as DECIMAL(12,2))

AND cast(field_value_max AS DECIMAL(12,2)) <= cast(‘540022000’ as DECIMAL(12,2))

This is called for each of the filters that we have.

Please note that on our dev env we had to remove the search & filter pro plugin in order for other tasks to be tested on it. However on tuesday I will put it back on.

Thank you and have a nice day!