Set ElasticPress Exact match

set-exact.php

function set_to_exact( $formatted_args, $args ) {
    if ( ! empty( $formatted_args['query']['bool']['should'] ) ) {
        $formatted_args['query']['bool']['must'] = $formatted_args['query']['bool']['should'];
        $formatted_args['query']['bool']['must'][0]['multi_match']['operator'] = 'AND';
        unset( $formatted_args['query']['bool']['should'] );
        unset( $formatted_args["query"]["bool"]["must"][0]["multi_match"]["type"] );
    }
    return $formatted_args;
}
add_filter( 'ep_formatted_args', 'set_to_exact', 10, 2 );